Shescape on Windows escaping may be bypassed in threaded context

@@ -7,6 +7,7 @@ Versioning].
 
 ## [Unreleased]
 
+- Fix potential silent executable lookup failure for Windows. ([#1142])
 - Support more valid `shell` values for Windows. ([#1137])
 
 ## [1.7.3] - 2023-08-07
@@ -292,6 +293,7 @@ Versioning].
 [#1083]: https://github.com/ericcornelissen/shescape/pull/1083
 [#1094]: https://github.com/ericcornelissen/shescape/pull/1094
 [#1137]: https://github.com/ericcornelissen/shescape/pull/1137
+[#1142]: https://github.com/ericcornelissen/shescape/pull/1142
 [552e8ea]: https://github.com/ericcornelissen/shescape/commit/552e8eab56861720b1d4e5474fb65741643358f9
 [keep a changelog]: https://keepachangelog.com/en/1.0.0/
 [semantic versioning]: https://semver.org/spec/v2.0.0.html

@@ -53,7 +53,7 @@ function getPlatformHelpers() {
 export function escape(arg, options = {}) {
   const helpers = getPlatformHelpers();
   const { flagProtection, interpolation, shellName } = parseOptions(
-    { options, process },
+    { env: process.env, options },
     helpers,
   );
   const argAsString = checkedToString(arg);
@@ -129,7 +129,7 @@ export function escapeAll(args, options = {}) {
 export function quote(arg, options = {}) {
   const helpers = getPlatformHelpers();
   const { flagProtection, shellName } = parseOptions(
-    { options, process },
+    { env: process.env, options },
     helpers,
   );
   const argAsString = checkedToString(arg);

@@ -12,16 +12,20 @@
  * - Follows symbolic links.
  *
  * @param {object} args The arguments for this function.
+ * @param {object} args.env The environment variables.
  * @param {string} args.executable A string representation of the executable.
  * @param {object} deps The dependencies for this function.
  * @param {Function} deps.exists A function to check if a file exists.
  * @param {Function} deps.readlink A function to resolve (sym)links.
  * @param {Function} deps.which A function to perform a `which(1)`-like lookup.
  * @returns {string} The full path to the binary of the executable.
  */
-export function resolveExecutable({ executable }, { exists, readlink, which }) {
+export function resolveExecutable(
+  { env, executable },
+  { exists, readlink, which },
+) {
   try {
-    executable = which(executable);
+    executable = which(executable, { path: env.PATH || env.Path });
   } catch (_) {
     // For backwards compatibility return the executable even if its location
     // cannot be obtained

@@ -10,25 +10,24 @@ import { isString } from "./reflection.js";
  * Parses options provided to shescape.
  *
  * @param {object} args The arguments for this function.
+ * @param {object} args.env The environment variables.
  * @param {object} args.options The options for escaping.
  * @param {boolean} [args.options.flagProtection] Is flag protection enabled.
  * @param {boolean} [args.options.interpolation] Is interpolation enabled.
  * @param {boolean | string} [args.options.shell] The shell to escape for.
- * @param {object} args.process The `process` values.
- * @param {object} args.process.env The environment variables.
  * @param {object} deps The dependencies for this function.
  * @param {Function} deps.getDefaultShell Function to get the default shell.
  * @param {Function} deps.getShellName Function to get the name of a shell.
  * @returns {object} The parsed arguments.
  */
 export function parseOptions(
-  { options: { flagProtection, interpolation, shell }, process: { env } },
+  { env, options: { flagProtection, interpolation, shell } },
   { getDefaultShell, getShellName },
 ) {
   flagProtection = flagProtection ? true : false;
   interpolation = interpolation ? true : false;
   shell = isString(shell) ? shell : getDefaultShell({ env });
 
-  const shellName = getShellName({ shell }, { resolveExecutable });
+  const shellName = getShellName({ env, shell }, { resolveExecutable });
   return { flagProtection, interpolation, shellName };
 }

@@ -121,14 +121,15 @@ export function getFlagProtectionFunction(shellName) {
  * Determines the name of the shell identified by a file path or file name.
  *
  * @param {object} args The arguments for this function.
+ * @param {object} args.env The environment variables.
  * @param {string} args.shell The name or path of the shell.
  * @param {object} deps The dependencies for this function.
  * @param {Function} deps.resolveExecutable Resolve the path to an executable.
  * @returns {string} The shell name.
  */
-export function getShellName({ shell }, { resolveExecutable }) {
+export function getShellName({ env, shell }, { resolveExecutable }) {
   shell = resolveExecutable(
-    { executable: shell },
+    { env, executable: shell },
     { exists: fs.existsSync, readlink: fs.readlinkSync, which: which.sync },
   );
 

@@ -98,14 +98,15 @@ export function getFlagProtectionFunction(shellName) {
  * Determines the name of the shell identified by a file path or file name.
  *
  * @param {object} args The arguments for this function.
+ * @param {object} args.env The environment variables.
  * @param {string} args.shell The name or path of the shell.
  * @param {object} deps The dependencies for this function.
  * @param {Function} deps.resolveExecutable Resolve the path to an executable.
  * @returns {string} The shell name.
  */
-export function getShellName({ shell }, { resolveExecutable }) {
+export function getShellName({ env, shell }, { resolveExecutable }) {
   shell = resolveExecutable(
-    { executable: shell },
+    { env, executable: shell },
     { exists: fs.existsSync, readlink: fs.readlinkSync, which: which.sync },
   );
 

@@ -60,11 +60,13 @@ module.exports.shellsUnix = [
 
 /* Windows related constants */
 module.exports.binCmd = "cmd.exe";
+module.exports.binCmdNoExt = "cmd";
 module.exports.binPowerShell = "powershell.exe";
+module.exports.binPowerShellNoExt = "powershell";
 
 module.exports.shellsWindows = [
   module.exports.binCmd,
-  "cmd.EXE",
+  module.exports.binCmdNoExt,
   module.exports.binPowerShell,
-  "powershell.EXE",
+  module.exports.binPowerShellNoExt,
 ];

@@ -1,40 +0,0 @@
-/**
- * @overview Contains end-to-end tests of using Shescape with the child_process
- * package.
- * @license MIT
- */
-
-import test from "ava";
-import isCI from "is-ci";
-import which from "which";
-
-import { constants, macros, injectionStrings } from "./_.js";
-
-const systemShells = constants.isWindows
-  ? constants.shellsWindows
-  : constants.shellsUnix;
-
-const testArgs = ["harmless", ...injectionStrings];
-const testShells = [false, true, ...systemShells];
-
-for (const arg of testArgs) {
-  test(macros.fork, { arg });
-
-  for (const shell of testShells) {
-    let runTest = test;
-    try {
-      if (!isCI && typeof shell === "string") {
-        which.sync(shell);
-      }
-    } catch (_) {
-      runTest = test.skip;
-    }
-
-    runTest(macros.exec, { arg, shell });
-    runTest(macros.execSync, { arg, shell });
-    runTest(macros.execFile, { arg, shell });
-    runTest(macros.execFileSync, { arg, shell });
-    runTest(macros.spawn, { arg, shell });
-    runTest(macros.spawnSync, { arg, shell });
-  }
-}

@@ -0,0 +1,53 @@
+/**
+ * @overview Provides common utilities for end-to-end tests.
+ * @license MIT
+ */
+
+import process from "node:process";
+
+import test from "ava";
+import isCI from "is-ci";
+import which from "which";
+
+import { injectionStrings } from "../../testing.js";
+import * as constants from "../_constants.cjs";
+
+/**
+ * Get a list of strings to use as arguments in end-to-end tests.
+ *
+ * @returns {string[]} A list of test arguments.
+ */
+export function getTestArgs() {
+  return ["harmless", ...injectionStrings];
+}
+
+/**
+ * Get the AVA test function to use for the given shell.
+ *
+ * @param {string} shell The shell to run a test for.
+ * @returns {Function} An AVA `test` function.
+ */
+export function getTestFn(shell) {
+  try {
+    if (!isCI && typeof shell === "string") {
+      which.sync(shell, { path: process.env.PATH || process.env.Path });
+    }
+
+    return test;
+  } catch (_) {
+    return test.skip;
+  }
+}
+
+/**
+ * Get a list of `shell` option values to use in end-to-end tests.
+ *
+ * @returns {(boolean | string)[]} A list of `shell` option values.
+ */
+export function getTestShells() {
+  const systemShells = constants.isWindows
+    ? constants.shellsWindows
+    : constants.shellsUnix;
+
+  return [false, true, ...systemShells];
+}

@@ -0,0 +1,15 @@
+/**
+ * @overview Contains end-to-end tests of using Shescape with the child_process
+ * package's `execFile` (and `execFileSync`) functions.
+ * @license MIT
+ */
+
+import { common, macros } from "./_.js";
+
+for (const shell of common.getTestShells()) {
+  const test = common.getTestFn(shell);
+  for (const arg of common.getTestArgs()) {
+    test(macros.execFile, { arg, shell });
+    test(macros.execFileSync, { arg, shell });
+  }
+}

@@ -0,0 +1,15 @@
+/**
+ * @overview Contains end-to-end tests of using Shescape with the child_process
+ * package's `exec` (and `execSync`) functions.
+ * @license MIT
+ */
+
+import { common, macros } from "./_.js";
+
+for (const shell of common.getTestShells()) {
+  const test = common.getTestFn(shell);
+  for (const arg of common.getTestArgs()) {
+    test(macros.exec, { arg, shell });
+    test(macros.execSync, { arg, shell });
+  }
+}

@@ -0,0 +1,12 @@
+/**
+ * @overview Contains end-to-end tests of using Shescape with the child_process
+ * package's `fork` functions.
+ * @license MIT
+ */
+
+import { common, macros } from "./_.js";
+
+for (const arg of common.getTestArgs()) {
+  const test = common.getTestFn(null);
+  test(macros.fork, { arg });
+}

@@ -3,8 +3,8 @@
  * @license MIT
  */
 
-import { injectionStrings } from "../../testing.js";
 import * as constants from "../_constants.cjs";
+import * as common from "./_common.js";
 import * as macros from "./_macros.js";
 
-export { constants, macros, injectionStrings };
+export { common, constants, macros };

@@ -0,0 +1,15 @@
+/**
+ * @overview Contains end-to-end tests of using Shescape with the child_process
+ * package's `spawn` (and `spawnSync`) functions.
+ * @license MIT
+ */
+
+import { common, macros } from "./_.js";
+
+for (const shell of common.getTestShells()) {
+  const test = common.getTestFn(shell);
+  for (const arg of common.getTestArgs()) {
+    test(macros.spawn, { arg, shell });
+    test(macros.spawnSync, { arg, shell });
+  }
+}

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escapeAll` for the
+ * Bourne-again shell (Bash).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escapeAll } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binBash}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binBash)) {
+    const { expected, input, options } = scenario;
+    const result = escapeAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escapeAll` for the Windows
+ * Command Prompt (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escapeAll } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binCmd}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binCmd)) {
+    const { expected, input, options } = scenario;
+    const result = escapeAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escapeAll` for the Windows
+ * Command Prompt (without extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escapeAll } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binCmdNoExt}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binCmdNoExt)) {
+    const { expected, input, options } = scenario;
+    const result = escapeAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,23 @@
+/**
+ * @overview Contains integration test for the CommonJS version of
+ * `shescape.escapeAll`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+import * as fc from "fast-check";
+
+import { arbitrary } from "../_.js";
+
+import { escapeAll } from "shescape";
+import { escapeAll as escapeAllCjs } from "../../../index.cjs";
+
+testProp(
+  "esm === cjs",
+  [fc.array(arbitrary.shescapeArg()), arbitrary.shescapeOptions()],
+  (t, args, options) => {
+    const resultEsm = escapeAll(args, options);
+    const resultCjs = escapeAllCjs(args, options);
+    t.deepEqual(resultEsm, resultCjs);
+  },
+);

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escapeAll` for the C shell
+ * (csh).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escapeAll } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binCsh}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binCsh)) {
+    const { expected, input, options } = scenario;
+    const result = escapeAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escapeAll` for the Debian
+ * Almquist shell (Dash).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escapeAll } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binDash}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binDash)) {
+    const { expected, input, options } = scenario;
+    const result = escapeAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,22 @@
+/**
+ * @overview Contains integration tests for invalid use of `shescape.escapeAll`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+import test from "ava";
+
+import { arbitrary, constants, macros } from "../_.js";
+
+import { escapeAll } from "shescape";
+
+testProp("invalid arguments", [arbitrary.shescapeOptions()], (t, options) => {
+  for (const { value } of constants.illegalArguments) {
+    t.throws(() => escapeAll([value], options), { instanceOf: TypeError });
+    t.throws(() => escapeAll(value, options), { instanceOf: TypeError });
+  }
+});
+
+test(macros.prototypePollution, (_, payload) => {
+  escapeAll(["a"], payload);
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escapeAll` for Windows
+ * PowerShell (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escapeAll } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binPowerShell}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binPowerShell)) {
+    const { expected, input, options } = scenario;
+    const result = escapeAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,23 @@
+/**
+ * @overview Contains integration tests for `shescape.escapeAll` for Windows
+ * PowerShell (without extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escapeAll } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binPowerShellNoExt}`, (t) => {
+  for (const scenario of generate.escapeExamples(
+    constants.binPowerShellNoExt,
+  )) {
+    const { expected, input, options } = scenario;
+    const result = escapeAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -1,25 +1,14 @@
 /**
- * @overview Contains integration tests for `shescape.escapeAll`.
+ * @overview Contains integration tests for valid use of `shescape.escapeAll`.
  * @license MIT
  */
 
 import { testProp } from "@fast-check/ava";
-import test from "ava";
 import * as fc from "fast-check";
 
-import { arbitrary, constants, generate, macros } from "./_.js";
+import { arbitrary } from "../_.js";
 
 import { escape, escapeAll } from "shescape";
-import { escapeAll as escapeAllCjs } from "../../index.cjs";
-
-for (const shell of generate.platformShells()) {
-  test(`inputs are escaped for ${shell}`, (t) => {
-    for (const { expected, input, options } of generate.escapeExamples(shell)) {
-      const result = escapeAll([input], options);
-      t.deepEqual(result, [expected]);
-    }
-  });
-}
 
 testProp(
   "return values",
@@ -71,24 +60,3 @@ testProp(
     t.is(entry, escape(arg, options));
   },
 );
-
-testProp("invalid arguments", [arbitrary.shescapeOptions()], (t, options) => {
-  for (const { value } of constants.illegalArguments) {
-    t.throws(() => escapeAll([value], options), { instanceOf: TypeError });
-    t.throws(() => escapeAll(value, options), { instanceOf: TypeError });
-  }
-});
-
-test(macros.prototypePollution, (_, payload) => {
-  escapeAll(["a"], payload);
-});
-
-testProp(
-  "esm === cjs",
-  [fc.array(arbitrary.shescapeArg()), arbitrary.shescapeOptions()],
-  (t, args, options) => {
-    const resultEsm = escapeAll(args, options);
-    const resultCjs = escapeAllCjs(args, options);
-    t.deepEqual(resultEsm, resultCjs);
-  },
-);

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escapeAll` for the Z shell
+ * (Zsh).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escapeAll } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binZsh}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binZsh)) {
+    const { expected, input, options } = scenario;
+    const result = escapeAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quote` for the
+ * Bourne-again shell (Bash).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quote } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binBash}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binBash)) {
+    const { expected, input, options } = scenario;
+    const result = quote(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escape` for the Windows
+ * Command Prompt (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escape } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binCmd}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binCmd)) {
+    const { expected, input, options } = scenario;
+    const result = escape(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escape` for the Windows
+ * Command Prompt (without extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escape } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binCmdNoExt}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binCmdNoExt)) {
+    const { expected, input, options } = scenario;
+    const result = escape(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,22 @@
+/**
+ * @overview Contains integration tests for the CommonJS version of
+ * `shescape.escape`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+
+import { arbitrary } from "../_.js";
+
+import { escape } from "shescape";
+import { escape as escapeCjs } from "../../../index.cjs";
+
+testProp(
+  "esm === cjs",
+  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
+  (t, arg, options) => {
+    const resultEsm = escape(arg, options);
+    const resultCjs = escapeCjs(arg, options);
+    t.is(resultEsm, resultCjs);
+  },
+);

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escape` for the C shell
+ * (csh).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escape } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binCsh}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binCsh)) {
+    const { expected, input, options } = scenario;
+    const result = escape(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escape` for the Debian
+ * Almquist shell (Dash).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escape } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binDash}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binDash)) {
+    const { expected, input, options } = scenario;
+    const result = escape(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for invalid use of `shescape.escape`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+import test from "ava";
+
+import { arbitrary, constants, macros } from "../_.js";
+
+import { escape } from "shescape";
+
+testProp("invalid arguments", [arbitrary.shescapeOptions()], (t, options) => {
+  for (const { value } of constants.illegalArguments) {
+    t.throws(() => escape(value, options), { instanceOf: TypeError });
+  }
+});
+
+test(macros.prototypePollution, (_, payload) => {
+  escape("a", payload);
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escape` for Windows
+ * PowerShell (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escape } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binPowerShell}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binPowerShell)) {
+    const { expected, input, options } = scenario;
+    const result = escape(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,23 @@
+/**
+ * @overview Contains integration tests for `shescape.escape` for Windows
+ * PowerShell (without extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escape } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binPowerShellNoExt}`, (t) => {
+  for (const scenario of generate.escapeExamples(
+    constants.binPowerShellNoExt,
+  )) {
+    const { expected, input, options } = scenario;
+    const result = escape(input, options);
+    t.is(result, expected);
+  }
+});

@@ -1,50 +0,0 @@
-/**
- * @overview Contains integration tests for `shescape.escape`.
- * @license MIT
- */
-
-import { testProp } from "@fast-check/ava";
-import test from "ava";
-
-import { arbitrary, constants, generate, macros } from "./_.js";
-
-import { escape as escape } from "shescape";
-import { escape as escapeCjs } from "../../index.cjs";
-
-for (const shell of generate.platformShells()) {
-  test(`input is escaped for ${shell}`, (t) => {
-    for (const { expected, input, options } of generate.escapeExamples(shell)) {
-      const result = escape(input, options);
-      t.is(result, expected);
-    }
-  });
-}
-
-testProp(
-  "return values",
-  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
-  (t, arg, options) => {
-    const result = escape(arg, options);
-    t.is(typeof result, "string");
-  },
-);
-
-testProp("invalid arguments", [arbitrary.shescapeOptions()], (t, options) => {
-  for (const { value } of constants.illegalArguments) {
-    t.throws(() => escape(value, options), { instanceOf: TypeError });
-  }
-});
-
-test(macros.prototypePollution, (_, payload) => {
-  escape("a", payload);
-});
-
-testProp(
-  "esm === cjs",
-  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
-  (t, arg, options) => {
-    const resultEsm = escape(arg, options);
-    const resultCjs = escapeCjs(arg, options);
-    t.is(resultEsm, resultCjs);
-  },
-);

@@ -0,0 +1,19 @@
+/**
+ * @overview Contains integration tests for valid use of `shescape.escape`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+
+import { arbitrary } from "../_.js";
+
+import { escape } from "shescape";
+
+testProp(
+  "return values",
+  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
+  (t, arg, options) => {
+    const result = escape(arg, options);
+    t.is(typeof result, "string");
+  },
+);

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escape` for the Z shell
+ * (Zsh).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escape } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binZsh}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binZsh)) {
+    const { expected, input, options } = scenario;
+    const result = escape(input, options);
+    t.is(result, expected);
+  }
+});

@@ -5,28 +5,16 @@
 
 import * as fixturesUnix from "../fixtures/unix.js";
 import * as fixturesWindows from "../fixtures/win.js";
-import common from "../_constants.cjs";
 
-/**
- * Returns the shells officially supported by Shescape for the current platform.
- *
- * @yields {string} Supported shells for the current platform.
- */
-export function* platformShells() {
-  if (common.isWindows) {
-    yield* common.shellsWindows;
-  } else {
-    yield* common.shellsUnix;
-  }
-}
+import { constants } from "./_.js";
 
 /**
  * Returns the test fixtures for the current platform.
  *
  * @returns {object} All test fixtures for the current platform.
  */
 function getPlatformFixtures() {
-  if (common.isWindows) {
+  if (constants.isWindows) {
     return fixturesWindows;
   } else {
     return fixturesUnix;
@@ -40,13 +28,16 @@ function getPlatformFixtures() {
  * @returns {object} All test fixtures for `shell`.
  */
 function getShellFixtures(shell) {
-  shell = shell.toLowerCase();
+  let shellName = shell.toLowerCase();
+  if (constants.isWindows) {
+    shellName = shellName.endsWith(".exe") ? shellName : `${shellName}.exe`;
+  }
 
   const fixtures = getPlatformFixtures();
   return {
-    escape: Object.values(fixtures.escape[shell]).flat(),
-    flag: Object.values(fixtures.flag[shell]).flat(),
-    quote: Object.values(fixtures.quote[shell]).flat(),
+    escape: Object.values(fixtures.escape[shellName]).flat(),
+    flag: Object.values(fixtures.flag[shellName]).flat(),
+    quote: Object.values(fixtures.quote[shellName]).flat(),
   };
 }
 

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quoteAll` for the
+ * Bourne-again shell (Bash).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quoteAll } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binBash}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binBash)) {
+    const { expected, input, options } = scenario;
+    const result = quoteAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quoteAll` for the Windows
+ * Command Prompt (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quoteAll } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binCmd}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binCmd)) {
+    const { expected, input, options } = scenario;
+    const result = quoteAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quoteAll` for the Windows
+ * Command Prompt (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quoteAll } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binCmdNoExt}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binCmdNoExt)) {
+    const { expected, input, options } = scenario;
+    const result = quoteAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,23 @@
+/**
+ * @overview Contains integration test for the CommonJS version of
+ * `shescape.quoteAll`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+import * as fc from "fast-check";
+
+import { arbitrary } from "../_.js";
+
+import { quoteAll } from "shescape";
+import { quoteAll as quoteAllCjs } from "../../../index.cjs";
+
+testProp(
+  "esm === cjs",
+  [fc.array(arbitrary.shescapeArg()), arbitrary.shescapeOptions()],
+  (t, args, options) => {
+    const resultEsm = quoteAll(args, options);
+    const resultCjs = quoteAllCjs(args, options);
+    t.deepEqual(resultEsm, resultCjs);
+  },
+);

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quoteAll` for the C shell
+ * (csh).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quoteAll } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binCsh}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binCsh)) {
+    const { expected, input, options } = scenario;
+    const result = quoteAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quoteAll` for the Debian
+ * Almquist shell (Dash).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quoteAll } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binDash}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binDash)) {
+    const { expected, input, options } = scenario;
+    const result = quoteAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,22 @@
+/**
+ * @overview Contains integration tests for invalid use of `shescape.quote`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+import test from "ava";
+
+import { arbitrary, constants, macros } from "../_.js";
+
+import { quoteAll } from "shescape";
+
+testProp("invalid arguments", [arbitrary.shescapeOptions()], (t, options) => {
+  for (const { value } of constants.illegalArguments) {
+    t.throws(() => quoteAll([value], options), { instanceOf: TypeError });
+    t.throws(() => quoteAll(value, options), { instanceOf: TypeError });
+  }
+});
+
+test(macros.prototypePollution, (_, payload) => {
+  quoteAll(["a"], payload);
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quoteAll` for Windows
+ * PowerShell (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quoteAll } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binPowerShell}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binPowerShell)) {
+    const { expected, input, options } = scenario;
+    const result = quoteAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quoteAll` for Windows
+ * PowerShell (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quoteAll } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binPowerShellNoExt}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binPowerShellNoExt)) {
+    const { expected, input, options } = scenario;
+    const result = quoteAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -1,25 +1,14 @@
 /**
- * @overview Contains integration tests for `shescape.quoteAll`.
+ * @overview Contains integration tests for valid use of `shescape.quoteAll`.
  * @license MIT
  */
 
 import { testProp } from "@fast-check/ava";
-import test from "ava";
 import * as fc from "fast-check";
 
-import { arbitrary, constants, generate, macros } from "./_.js";
+import { arbitrary } from "../_.js";
 
 import { quote, quoteAll as quoteAll } from "shescape";
-import { quoteAll as quoteAllCjs } from "../../index.cjs";
-
-for (const shell of generate.platformShells()) {
-  test(`inputs are quoted for ${shell}`, (t) => {
-    for (const { expected, input, options } of generate.quoteExamples(shell)) {
-      const result = quoteAll([input], options);
-      t.deepEqual(result, [expected]);
-    }
-  });
-}
 
 testProp(
   "return values",
@@ -71,24 +60,3 @@ testProp(
     t.is(entry, quote(arg, options));
   },
 );
-
-testProp("invalid arguments", [arbitrary.shescapeOptions()], (t, options) => {
-  for (const { value } of constants.illegalArguments) {
-    t.throws(() => quoteAll([value], options), { instanceOf: TypeError });
-    t.throws(() => quoteAll(value, options), { instanceOf: TypeError });
-  }
-});
-
-test(macros.prototypePollution, (_, payload) => {
-  quoteAll(["a"], payload);
-});
-
-testProp(
-  "esm === cjs",
-  [fc.array(arbitrary.shescapeArg()), arbitrary.shescapeOptions()],
-  (t, args, options) => {
-    const resultEsm = quoteAll(args, options);
-    const resultCjs = quoteAllCjs(args, options);
-    t.deepEqual(resultEsm, resultCjs);
-  },
-);

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quoteAll` for the Z shell
+ * (Zsh).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quoteAll } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binZsh}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binZsh)) {
+    const { expected, input, options } = scenario;
+    const result = quoteAll([input], options);
+    t.deepEqual(result, [expected]);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.escape` for the
+ * Bourne-again shell (Bash).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { escape } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binBash}`, (t) => {
+  for (const scenario of generate.escapeExamples(constants.binBash)) {
+    const { expected, input, options } = scenario;
+    const result = escape(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quote` for the Windows
+ * Command Prompt (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quote } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binCmd}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binCmd)) {
+    const { expected, input, options } = scenario;
+    const result = quote(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quote` for the Windows
+ * Command Prompt (without extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quote } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binCmdNoExt}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binCmdNoExt)) {
+    const { expected, input, options } = scenario;
+    const result = quote(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,22 @@
+/**
+ * @overview Contains integration tests for the CommonJS version of
+ * `shescape.quote`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+
+import { arbitrary } from "../_.js";
+
+import { quote } from "shescape";
+import { quote as quoteCjs } from "../../../index.cjs";
+
+testProp(
+  "esm === cjs",
+  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
+  (t, arg, options) => {
+    const resultEsm = quote(arg, options);
+    const resultCjs = quoteCjs(arg, options);
+    t.is(resultEsm, resultCjs);
+  },
+);

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quote` for the C shell
+ * (csh).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quote } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binCsh}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binCsh)) {
+    const { expected, input, options } = scenario;
+    const result = quote(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quote` for the Debian
+ * Almquist shell (Dash).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quote } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binDash}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binDash)) {
+    const { expected, input, options } = scenario;
+    const result = quote(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for invalid use of `shescape.quote`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+import test from "ava";
+
+import { arbitrary, constants, macros } from "../_.js";
+
+import { quote } from "shescape";
+
+testProp("invalid arguments", [arbitrary.shescapeOptions()], (t, options) => {
+  for (const { value } of constants.illegalArguments) {
+    t.throws(() => quote(value, options), { instanceOf: TypeError });
+  }
+});
+
+test(macros.prototypePollution, (_, payload) => {
+  quote("a", payload);
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quote` for Windows
+ * PowerShell (with extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quote } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binPowerShell}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binPowerShell)) {
+    const { expected, input, options } = scenario;
+    const result = quote(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quote` for Windows
+ * PowerShell (without extension).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quote } from "shescape";
+
+const runTest = constants.isWindows ? test : test.skip;
+
+runTest(`input is escaped for ${constants.binPowerShellNoExt}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binPowerShellNoExt)) {
+    const { expected, input, options } = scenario;
+    const result = quote(input, options);
+    t.is(result, expected);
+  }
+});

@@ -1,50 +0,0 @@
-/**
- * @overview Contains integration tests for `shescape.quote`.
- * @license MIT
- */
-
-import { testProp } from "@fast-check/ava";
-import test from "ava";
-
-import { arbitrary, constants, generate, macros } from "./_.js";
-
-import { quote as quote } from "shescape";
-import { quote as quoteCjs } from "../../index.cjs";
-
-for (const shell of generate.platformShells()) {
-  test(`input is quoted for ${shell}`, (t) => {
-    for (const { expected, input, options } of generate.quoteExamples(shell)) {
-      const result = quote(input, options);
-      t.is(result, expected);
-    }
-  });
-}
-
-testProp(
-  "return value",
-  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
-  (t, arg, options) => {
-    const result = quote(arg, options);
-    t.is(typeof result, "string");
-  },
-);
-
-testProp("invalid arguments", [arbitrary.shescapeOptions()], (t, options) => {
-  for (const { value } of constants.illegalArguments) {
-    t.throws(() => quote(value, options), { instanceOf: TypeError });
-  }
-});
-
-test(macros.prototypePollution, (_, payload) => {
-  quote("a", payload);
-});
-
-testProp(
-  "esm === cjs",
-  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
-  (t, arg, options) => {
-    const resultEsm = quote(arg, options);
-    const resultCjs = quoteCjs(arg, options);
-    t.is(resultEsm, resultCjs);
-  },
-);

@@ -0,0 +1,19 @@
+/**
+ * @overview Contains integration tests for valid use of `shescape.quote`.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+
+import { arbitrary } from "../_.js";
+
+import { quote } from "shescape";
+
+testProp(
+  "return value",
+  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
+  (t, arg, options) => {
+    const result = quote(arg, options);
+    t.is(typeof result, "string");
+  },
+);

@@ -0,0 +1,21 @@
+/**
+ * @overview Contains integration tests for `shescape.quote` for the Z shell
+ * (Zsh).
+ * @license MIT
+ */
+
+import test from "ava";
+
+import { constants, generate } from "../_.js";
+
+import { quote } from "shescape";
+
+const runTest = constants.isWindows ? test.skip : test;
+
+runTest(`input is escaped for ${constants.binZsh}`, (t) => {
+  for (const scenario of generate.quoteExamples(constants.binZsh)) {
+    const { expected, input, options } = scenario;
+    const result = quote(input, options);
+    t.is(result, expected);
+  }
+});

@@ -0,0 +1,53 @@
+/**
+ * @overview Contains integration tests for the CommonJS version of the testing
+ * implementation of shescape.
+ * @license MIT
+ */
+
+import { testProp } from "@fast-check/ava";
+import * as fc from "fast-check";
+
+import { arbitrary } from "../_.js";
+
+import { shescape as stubscape } from "shescape/testing";
+import { shescape as stubscapeCjs } from "../../../testing.cjs";
+
+testProp(
+  "escape (esm === cjs)",
+  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
+  (t, arg, options) => {
+    const resultEsm = stubscape.escape(arg, options);
+    const resultCjs = stubscapeCjs.escape(arg, options);
+    t.is(resultEsm, resultCjs);
+  },
+);
+
+testProp(
+  "escapeAll (esm === cjs)",
+  [fc.array(arbitrary.shescapeArg()), arbitrary.shescapeOptions()],
+  (t, args, options) => {
+    const resultEsm = stubscape.escapeAll(args, options);
+    const resultCjs = stubscapeCjs.escapeAll(args, options);
+    t.deepEqual(resultEsm, resultCjs);
+  },
+);
+
+testProp(
+  "quote (esm === cjs)",
+  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
+  (t, arg, options) => {
+    const resultEsm = stubscape.quote(arg, options);
+    const resultCjs = stubscapeCjs.quote(arg, options);
+    t.is(resultEsm, resultCjs);
+  },
+);
+
+testProp(
+  "quoteAll (esm === cjs)",
+  [fc.array(arbitrary.shescapeArg()), arbitrary.shescapeOptions()],
+  (t, args, options) => {
+    const resultEsm = stubscape.quoteAll(args, options);
+    const resultCjs = stubscapeCjs.quoteAll(args, options);
+    t.deepEqual(resultEsm, resultCjs);
+  },
+);

@@ -7,11 +7,10 @@
 import { testProp } from "@fast-check/ava";
 import * as fc from "fast-check";
 
-import { arbitrary } from "./_.js";
+import { arbitrary } from "../_.js";
 
 import * as shescape from "shescape";
 import { shescape as stubscape } from "shescape/testing";
-import { shescape as stubscapeCjs } from "../../testing.cjs";
 
 testProp(
   "escape (stubscape ~ shescape)",
@@ -104,43 +103,3 @@ testProp(
     t.is(typeof result, typeof stubResult);
   },
 );
-
-testProp(
-  "escape (esm === cjs)",
-  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
-  (t, arg, options) => {
-    const resultEsm = stubscape.escape(arg, options);
-    const resultCjs = stubscapeCjs.escape(arg, options);
-    t.is(resultEsm, resultCjs);
-  },
-);
-
-testProp(
-  "escapeAll (esm === cjs)",
-  [fc.array(arbitrary.shescapeArg()), arbitrary.shescapeOptions()],
-  (t, args, options) => {
-    const resultEsm = stubscape.escapeAll(args, options);
-    const resultCjs = stubscapeCjs.escapeAll(args, options);
-    t.deepEqual(resultEsm, resultCjs);
-  },
-);
-
-testProp(
-  "quote (esm === cjs)",
-  [arbitrary.shescapeArg(), arbitrary.shescapeOptions()],
-  (t, arg, options) => {
-    const resultEsm = stubscape.quote(arg, options);
-    const resultCjs = stubscapeCjs.quote(arg, options);
-    t.is(resultEsm, resultCjs);
-  },
-);
-
-testProp(
-  "quoteAll (esm === cjs)",
-  [fc.array(arbitrary.shescapeArg()), arbitrary.shescapeOptions()],
-  (t, args, options) => {
-    const resultEsm = stubscape.quoteAll(args, options);
-    const resultCjs = stubscapeCjs.quoteAll(args, options);
-    t.deepEqual(resultEsm, resultCjs);
-  },
-);

@@ -0,0 +1,8 @@
+/**
+ * @overview Provides testing utilities.
+ * @license MIT
+ */
+
+import * as arbitrary from "../../_arbitraries.js";
+
+export { arbitrary };

@@ -3,9 +3,13 @@
  * @license MIT
  */
 
+import { testProp } from "@fast-check/ava";
 import test from "ava";
+import * as fc from "fast-check";
 import sinon from "sinon";
 
+import { arbitrary } from "./_.js";
+
 import { resolveExecutable } from "../../../src/executables.js";
 
 test.before((t) => {
@@ -16,7 +20,11 @@ test.before((t) => {
   t.not(executable, linkedExecutable);
   t.not(resolvedExecutable, linkedExecutable);
 
-  t.context = { executable, linkedExecutable, resolvedExecutable };
+  const env = {
+    PATH: "/bin:/usr/bin",
+  };
+
+  t.context = { env, executable, linkedExecutable, resolvedExecutable };
 });
 
 test.beforeEach((t) => {
@@ -27,25 +35,68 @@ test.beforeEach((t) => {
   t.context.deps = { exists, readlink, which };
 });
 
+testProp(
+  "env.PATH is defined",
+  [arbitrary.env({ keys: ["PATH", "Path"] }), fc.string({ minLength: 1 })],
+  (t, env, envPath) => {
+    t.context.deps.which.resetHistory();
+
+    env.PATH = envPath;
+
+    const { executable } = t.context;
+    const args = { env, executable };
+
+    resolveExecutable(args, t.context.deps);
+    t.is(t.context.deps.which.callCount, 1);
+    t.true(
+      t.context.deps.which.calledWithExactly(sinon.match.any, {
+        path: env.PATH,
+      }),
+    );
+  },
+);
+
+testProp(
+  "env.PATH is not defined",
+  [arbitrary.env({ keys: ["PATH", "Path"] }), fc.string({ minLength: 1 })],
+  (t, env, envPath) => {
+    t.context.deps.which.resetHistory();
+
+    delete env.PATH;
+    env.Path = envPath;
+
+    const { executable } = t.context;
+    const args = { env, executable };
+
+    resolveExecutable(args, t.context.deps);
+    t.is(t.context.deps.which.callCount, 1);
+    t.true(
+      t.context.deps.which.calledWithExactly(sinon.match.any, {
+        path: env.Path,
+      }),
+    );
+  },
+);
+
 test("the executable cannot be resolved", (t) => {
-  const { executable } = t.context;
-  const args = { executable };
+  const { env, executable } = t.context;
+  const args = { env, executable };
 
   t.context.deps.which.throws();
 
   const result = resolveExecutable(args, t.context.deps);
   t.is(result, executable);
 
   t.is(t.context.deps.which.callCount, 1);
-  t.true(t.context.deps.which.calledWithExactly(executable));
+  t.true(t.context.deps.which.calledWithExactly(executable, sinon.match.any));
 
   t.is(t.context.deps.exists.callCount, 0);
   t.is(t.context.deps.readlink.callCount, 0);
 });
 
 test("the executable doesn't exist", (t) => {
-  const { executable, resolvedExecutable } = t.context;
-  const args = { executable };
+  const { env, executable, resolvedExecutable } = t.context;
+  const args = { env, executable };
 
   t.context.deps.exists.returns(false);
   t.context.deps.which.returns(resolvedExecutable);
@@ -61,8 +112,8 @@ test("the executable doesn't exist", (t) => {
 });
 
 test("the executable exists and is not a (sym)link", (t) => {
-  const { executable, resolvedExecutable } = t.context;
-  const args = { executable };
+  const { env, executable, resolvedExecutable } = t.context;
+  const args = { env, executable };
 
   t.context.deps.exists.returns(true);
   t.context.deps.readlink.throws();
@@ -79,8 +130,8 @@ test("the executable exists and is not a (sym)link", (t) => {
 });
 
 test("the executable exists and is a (sym)link", (t) => {
-  const { executable, linkedExecutable, resolvedExecutable } = t.context;
-  const args = { executable };
+  const { env, executable, linkedExecutable, resolvedExecutable } = t.context;
+  const args = { env, executable };
 
   t.context.deps.exists.returns(true);
   t.context.deps.readlink.returns(linkedExecutable);

@@ -18,7 +18,7 @@ const arbitraryInput = () =>
     .tuple(arbitrary.shescapeOptions(), arbitrary.env())
     .map(([options, env]) => {
       options = options || {};
-      return { options, process: { env } };
+      return { env, options };
     });
 
 test.beforeEach((t) => {
@@ -84,7 +84,7 @@ testProp(
     t.context.deps.getShellName.resetHistory();
     t.context.deps.getShellName.returns(shellName);
 
-    const env = args.process.env;
+    const env = args.env;
     args.options.shell = providedShell;
 
     const result = parseOptions(args, t.context.deps);
@@ -93,7 +93,7 @@ testProp(
     t.is(t.context.deps.getShellName.callCount, 1);
     t.true(
       t.context.deps.getShellName.calledWithExactly(
-        { shell: defaultShell },
+        { env, shell: defaultShell },
         { resolveExecutable },
       ),
     );
@@ -108,14 +108,15 @@ testProp(
     t.context.deps.getShellName.resetHistory();
     t.context.deps.getShellName.returns(shellName);
 
+    const env = args.env;
     args.options.shell = providedShell;
 
     const result = parseOptions(args, t.context.deps);
     t.is(t.context.deps.getDefaultShell.callCount, 0);
     t.is(t.context.deps.getShellName.callCount, 1);
     t.true(
       t.context.deps.getShellName.calledWithExactly(
-        { shell: providedShell },
+        { env, shell: providedShell },
         { resolveExecutable },
       ),
     );

@@ -106,7 +106,7 @@ testProp(
     unix.getShellName({ env, shell }, { resolveExecutable });
     t.true(
       resolveExecutable.calledWithExactly(
-        { executable: shell },
+        { env, executable: shell },
         {
           exists: sinon.match.func,
           readlink: sinon.match.func,

@@ -99,11 +99,15 @@ testProp(
   "get shell name for supported shell",
   [arbitrary.env(), arbitrary.windowsPath(), arbitrary.windowsShell()],
   (t, env, basePath, shell) => {
+    const executable = shell.toLowerCase().endsWith(".exe")
+      ? shell
+      : `${shell}.exe`;
+
     const resolveExecutable = sinon.stub();
-    resolveExecutable.returns(path.join(basePath, shell));
+    resolveExecutable.returns(path.join(basePath, executable));
 
     const result = win.getShellName({ env, shell }, { resolveExecutable });
-    t.is(result, shell);
+    t.is(result, executable);
   },
 );
 
@@ -133,7 +137,7 @@ testProp(
     win.getShellName({ env, shell }, { resolveExecutable });
     t.true(
       resolveExecutable.calledWithExactly(
-        { executable: shell },
+        { env, executable: shell },
         {
           exists: sinon.match.func,
           readlink: sinon.match.func,