Repository: eslint/eslint
Pull request #12313 (2019-09-25 15:25:56)

Fix: prefer-numeric-literals autofix removes comments
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    ESLint adheres to the [JS Foundation Code of Conduct](https://js.foundation/community/code-of-conduct).
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**What is the purpose of this pull request? (put an "X" next to item)**

[X] Bug fix

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**Tell us about your environment**

* **ESLint Version:**  6.4.0
* **Node Version:** 10.16.0
* **npm Version:** 6.9.0

**What parser (default, Babel-ESLint, etc.) are you using?**

default

**Please show your full configuration:**

<details>
<summary>Configuration</summary>

<!-- Paste your configuration below: -->
```js
module.exports = {
  parserOptions: {
    ecmaVersion: 2015,
  }
};
```

</details>

**What did you do? Please include the actual source code causing the issue.**

[Online demo link](https://eslint.org/demo#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)

```js
/* eslint prefer-numeric-literals:error */

parseInt("11", /* comment */ 2);

Number // comment
    .parseInt("11", 2);
```

**What did you expect to happen?**

2 errors, but not to remove comments.

**What actually happened? Please include the actual, raw output from ESLint.**

```js
/* eslint prefer-numeric-literals:error */

0b11;

0b11;
```

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    - Read the pull request guide (https://eslint.org/docs/developer-guide/contributing/pull-requests)
    - Include tests for this change
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**What changes did you make? (Give an overview)**

Report errors but don't fix if that would remove any comments.

**Is there anything you'd like reviewers to focus on?**

I think that the rule might need 3-4 other modifications, but it's better to open another issue for that.



Patch:
diff --git a/bin/eslint.js b/bin/eslint.js
index 061e94767..82bcc1e03 100755
--- a/bin/eslint.js
+++ b/bin/eslint.js
@@ -16,9 +16,9 @@ require("v8-compile-cache");
 // Helpers
 //------------------------------------------------------------------------------
 
-const useStdIn = (process.argv.indexOf("--stdin") > -1),
-    init = (process.argv.indexOf("--init") > -1),
-    debug = (process.argv.indexOf("--debug") > -1);
+const useStdIn = process.argv.includes("--stdin"),
+    init = process.argv.includes("--init"),
+    debug = process.argv.includes("--debug");
 
 // must do this initialization *before* other requires in order to work
 if (debug) {
@@ -30,9 +30,9 @@ if (debug) {
 //------------------------------------------------------------------------------
 
 // now we can safely include the other modules that use debug
-const cli = require("../lib/cli"),
-    path = require("path"),
-    fs = require("fs");
+const path = require("path"),
+    fs = require("fs"),
+    cli = require("../lib/cli");
 
 //------------------------------------------------------------------------------
 // Execution
@@ -50,7 +50,6 @@ process.once("uncaughtException", err => {
         console.error("\nOops! Something went wrong! :(");
         console.error(`\nESLint: ${pkg.version}.\n\n${template(err.messageData || {})}`);
     } else {
-
         console.error(err.stack);
     }
 
diff --git a/docs/user-guide/command-line-interface.md b/docs/user-guide/command-line-interface.md
index 532d8f947..8938bc91f 100644
--- a/docs/user-guide/command-line-interface.md
+++ b/docs/user-guide/command-line-interface.md
@@ -78,6 +78,7 @@ Caching:
 
 Miscellaneous:
   --init                         Run config initialization wizard - default: false
+  --env-info                     Output execution environment information - default: false
   --debug                        Output debugging information
   -h, --help                     Show help
   -v, --version                  Output the version number
@@ -446,6 +447,10 @@ This option will start config initialization wizard. It's designed to help new u
 
 The resulting configuration file will be created in the current directory.
 
+#### `--env-info`
+
+This option outputs information about the execution environment, including the version of Node, npm, and local and global installations of ESLint. The ESLint team may ask for this information to help solve bugs.
+
 #### `--debug`
 
 This option outputs debugging information to the console. This information is useful when you're seeing a problem and having a hard time pinpointing it. The ESLint team may ask for this debugging information to help solve bugs.
diff --git a/lib/cli.js b/lib/cli.js
index c34545544..18a917cf0 100644
--- a/lib/cli.js
+++ b/lib/cli.js
@@ -20,7 +20,8 @@ const fs = require("fs"),
     mkdirp = require("mkdirp"),
     { CLIEngine } = require("./cli-engine"),
     options = require("./options"),
-    log = require("./shared/logging");
+    log = require("./shared/logging"),
+    RuntimeInfo = require("./shared/runtime-info");
 
 const debug = require("debug")("eslint:cli");
 
@@ -159,13 +160,18 @@ const cli = {
         }
 
         const files = currentOptions._;
-
         const useStdin = typeof text === "string";
 
-        if (currentOptions.version) { // version from package.json
-
-            log.info(`v${require("../package.json").version}`);
-
+        if (currentOptions.version) {
+            log.info(RuntimeInfo.version());
+        } else if (currentOptions.envInfo) {
+            try {
+                log.info(RuntimeInfo.environment());
+                return 0;
+            } catch (err) {
+                log.error(err.message);
+                return 2;
+            }
         } else if (currentOptions.printConfig) {
             if (files.length) {
                 log.error("The --print-config option must be used with exactly one file name.");
@@ -177,17 +183,13 @@ const cli = {
             }
 
             const engine = new CLIEngine(translateOptions(currentOptions));
-
             const fileConfig = engine.getConfigForFile(currentOptions.printConfig);
 
             log.info(JSON.stringify(fileConfig, null, "  "));
             return 0;
         } else if (currentOptions.help || (!files.length && !useStdin)) {
-
             log.info(options.generateHelp());
-
         } else {
-
             debug(`Running on ${useStdin ? "text" : "files"}`);
 
             if (currentOptions.fix && currentOptions.fixDryRun) {
@@ -227,9 +229,8 @@ const cli = {
 
                 return (report.errorCount || tooManyWarnings) ? 1 : 0;
             }
-            return 2;
-
 
+            return 2;
         }
 
         return 0;
diff --git a/lib/options.js b/lib/options.js
index 440773a84..83bf9afc2 100644
--- a/lib/options.js
+++ b/lib/options.js
@@ -224,6 +224,12 @@ module.exports = optionator({
             default: "false",
             description: "Run config initialization wizard"
         },
+        {
+            option: "env-info",
+            type: "Boolean",
+            default: "false",
+            description: "Output execution environment information"
+        },
         {
             option: "debug",
             type: "Boolean",
diff --git a/lib/rules/no-extra-parens.js b/lib/rules/no-extra-parens.js
index c5cf79047..c6809c355 100644
--- a/lib/rules/no-extra-parens.js
+++ b/lib/rules/no-extra-parens.js
@@ -205,7 +205,14 @@ module.exports = {
             const lastToken = sourceCode.getLastToken(newExpression);
             const penultimateToken = sourceCode.getTokenBefore(lastToken);
 
-            return newExpression.arguments.length > 0 || astUtils.isOpeningParenToken(penultimateToken) && astUtils.isClosingParenToken(lastToken);
+            return newExpression.arguments.length > 0 ||
+                (
+
+                    // The expression should end with its own parens, e.g., new new foo() is not a new expression with parens
+                    astUtils.isOpeningParenToken(penultimateToken) &&
+                    astUtils.isClosingParenToken(lastToken) &&
+                    newExpression.callee.range[1] < newExpression.range[1]
+                );
         }
 
         /**
@@ -338,7 +345,7 @@ module.exports = {
             function finishReport() {
                 context.report({
                     node,
-                    loc: leftParenToken.loc.start,
+                    loc: leftParenToken.loc,
                     messageId: "unexpected",
                     fix(fixer) {
                         const parenthesizedSource = sourceCode.text.slice(leftParenToken.range[1], rightParenToken.range[0]);
@@ -887,6 +894,12 @@ module.exports = {
                     report(node.object);
                 }
 
+                if (nodeObjHasExcessParens &&
+                  node.object.type === "NewExpression" &&
+                  isNewExpressionWithParens(node.object)) {
+                    report(node.object);
+                }
+
                 if (node.computed && hasExcessParens(node.property)) {
                     report(node.property);
                 }
diff --git a/lib/rules/prefer-numeric-literals.js b/lib/rules/prefer-numeric-literals.js
index ca7358aa0..b4113a3b3 100644
--- a/lib/rules/prefer-numeric-literals.js
+++ b/lib/rules/prefer-numeric-literals.js
@@ -96,6 +96,10 @@ module.exports = {
                         fix(fixer) {
                             const newPrefix = prefixMap[node.arguments[1].value];
 
+                            if (sourceCode.getCommentsInside(node).length) {
+                                return null;
+                            }
+
                             if (+(newPrefix + node.arguments[0].value) !== parseInt(node.arguments[0].value, node.arguments[1].value)) {
 
                                 /*
diff --git a/lib/shared/runtime-info.js b/lib/shared/runtime-info.js
new file mode 100644
index 000000000..324f457d8
--- /dev/null
+++ b/lib/shared/runtime-info.js
@@ -0,0 +1,152 @@
+/**
+ * @fileoverview Utility to get information about the execution environment.
+ * @author Kai Cataldo
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const path = require("path");
+const spawn = require("cross-spawn");
+const { isEmpty } = require("lodash");
+const log = require("../shared/logging");
+const packageJson = require("../../package.json");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Checks if a path is a child of a directory.
+ * @param {string} parentPath - The parent path to check.
+ * @param {string} childPath - The path to check.
+ * @returns {boolean} Whether or not the given path is a child of a directory.
+ */
+function isChildOfDirectory(parentPath, childPath) {
+    return !path.relative(parentPath, childPath).startsWith("..");
+}
+
+/**
+ * Synchronously executes a shell command and formats the result.
+ * @param {string} cmd - The command to execute.
+ * @param {Array} args - The arguments to be executed with the command.
+ * @returns {string} The version returned by the command.
+ */
+function execCommand(cmd, args) {
+    const process = spawn.sync(cmd, args, { encoding: "utf8" });
+
+    if (process.error) {
+        throw process.error;
+    }
+
+    return process.stdout.trim();
+}
+
+/**
+ * Normalizes a version number.
+ * @param {string} versionStr - The string to normalize.
+ * @returns {string} The normalized version number.
+ */
+function normalizeVersionStr(versionStr) {
+    return versionStr.startsWith("v") ? versionStr : `v${versionStr}`;
+}
+
+/**
+ * Gets bin version.
+ * @param {string} bin - The bin to check.
+ * @returns {string} The normalized version returned by the command.
+ */
+function getBinVersion(bin) {
+    const binArgs = ["--version"];
+
+    try {
+        return normalizeVersionStr(execCommand(bin, binArgs));
+    } catch (e) {
+        log.error(`Error finding ${bin} version running the command \`${bin} ${binArgs.join(" ")}\``);
+        throw e;
+    }
+}
+
+/**
+ * Gets installed npm package version.
+ * @param {string} pkg - The package to check.
+ * @param {boolean} global - Whether to check globally or not.
+ * @returns {string} The normalized version returned by the command.
+ */
+function getNpmPackageVersion(pkg, { global = false } = {}) {
+    const npmBinArgs = ["bin", "-g"];
+    const npmLsArgs = ["ls", "--depth=0", "--json", "eslint"];
+
+    if (global) {
+        npmLsArgs.push("-g");
+    }
+
+    try {
+        const parsedStdout = JSON.parse(execCommand("npm", npmLsArgs));
+
+        /*
+         * Checking globally returns an empty JSON object, while local checks
+         * include the name and version of the local project.
+         */
+        if (isEmpty(parsedStdout) || !(parsedStdout.dependencies && parsedStdout.dependencies.eslint)) {
+            return "Not found";
+        }
+
+        const [, processBinPath] = process.argv;
+        let npmBinPath;
+
+        try {
+            npmBinPath = execCommand("npm", npmBinArgs);
+        } catch (e) {
+            log.error(`Error finding npm binary path when running command \`npm ${npmBinArgs.join(" ")}\``);
+            throw e;
+        }
+
+        const isGlobal = isChildOfDirectory(npmBinPath, processBinPath);
+        let pkgVersion = parsedStdout.dependencies.eslint.version;
+
+        if ((global && isGlobal) || (!global && !isGlobal)) {
+            pkgVersion += " (Currently used)";
+        }
+
+        return normalizeVersionStr(pkgVersion);
+    } catch (e) {
+        log.error(`Error finding ${pkg} version running the command \`npm ${npmLsArgs.join(" ")}\``);
+        throw e;
+    }
+}
+
+/**
+ * Generates and returns execution environment information.
+ * @returns {string} A string that contains execution environment information.
+ */
+function environment() {
+    return [
+        "Environment Info:",
+        "",
+        `Node version: ${getBinVersion("node")}`,
+        `npm version: ${getBinVersion("npm")}`,
+        `Local ESLint version: ${getNpmPackageVersion("eslint", { global: false })}`,
+        `Global ESLint version: ${getNpmPackageVersion("eslint", { global: true })}`
+    ].join("\n");
+}
+
+/**
+ * Returns version of currently executing ESLint.
+ * @returns {string} The version from the currently executing ESLint's package.json.
+ */
+function version() {
+    return `v${packageJson.version}`;
+}
+
+//------------------------------------------------------------------------------
+// Public Interface
+//------------------------------------------------------------------------------
+
+module.exports = {
+    environment,
+    version
+};


Test patch:
diff --git a/tests/lib/cli.js b/tests/lib/cli.js
index baae75b53..1b98fb137 100644
--- a/tests/lib/cli.js
+++ b/tests/lib/cli.js
@@ -29,14 +29,18 @@ const proxyquire = require("proxyquire").noCallThru().noPreserveCache();
 //------------------------------------------------------------------------------
 
 describe("cli", () => {
-
     let fixtureDir;
     const log = {
         info: sinon.spy(),
         error: sinon.spy()
     };
+    const RuntimeInfo = {
+        environment: sinon.stub(),
+        version: sinon.stub()
+    };
     const cli = proxyquire("../../lib/cli", {
-        "./shared/logging": log
+        "./shared/logging": log,
+        "./shared/runtime-info": RuntimeInfo
     });
 
     /**
@@ -324,15 +328,27 @@ describe("cli", () => {
     describe("when executing with version flag", () => {
         it("should print out current version", () => {
             assert.strictEqual(cli.execute("-v"), 0);
+            assert.strictEqual(log.info.callCount, 1);
+        });
+    });
 
+    describe("when executing with env-info flag", () => {
+        it("should print out environment information", () => {
+            assert.strictEqual(cli.execute("--env-info"), 0);
             assert.strictEqual(log.info.callCount, 1);
         });
+
+        it("should print error message and return error code", () => {
+            RuntimeInfo.environment.throws("There was an error!");
+
+            assert.strictEqual(cli.execute("--env-info"), 2);
+            assert.strictEqual(log.error.callCount, 1);
+        });
     });
 
     describe("when executing with help flag", () => {
         it("should print out help", () => {
             assert.strictEqual(cli.execute("-h"), 0);
-
             assert.strictEqual(log.info.callCount, 1);
         });
     });
@@ -349,7 +365,6 @@ describe("cli", () => {
     });
 
     describe("when given a file in excluded files list", () => {
-
         it("should not process the file", () => {
             const ignorePath = getFixturePath(".eslintignore");
             const filePath = getFixturePath("passing.js");
@@ -398,7 +413,6 @@ describe("cli", () => {
     });
 
     describe("when executing a file with a shebang", () => {
-
         it("should execute without error", () => {
             const filePath = getFixturePath("shebang.js");
             const exit = cli.execute(`--no-ignore ${filePath}`);
@@ -408,7 +422,6 @@ describe("cli", () => {
     });
 
     describe("when loading a custom rule", () => {
-
         it("should return an error when rule isn't found", () => {
             const rulesPath = getFixturePath("rules", "wrong");
             const configPath = getFixturePath("rules", "eslint.json");
@@ -551,7 +564,6 @@ describe("cli", () => {
     });
 
     describe("when supplied with report output file path", () => {
-
         afterEach(() => {
             sh.rm("-rf", "tests/output");
         });
@@ -594,7 +606,6 @@ describe("cli", () => {
     });
 
     describe("when supplied with a plugin", () => {
-
         it("should pass plugins to CLIEngine", () => {
             const examplePluginName = "eslint-plugin-example";
 
diff --git a/tests/lib/rules/no-extra-parens.js b/tests/lib/rules/no-extra-parens.js
index 788823e04..e42b5eadc 100644
--- a/tests/lib/rules/no-extra-parens.js
+++ b/tests/lib/rules/no-extra-parens.js
@@ -95,6 +95,17 @@ ruleTester.run("no-extra-parens", rule, {
         "new A()()",
         "(new A)()",
         "(new (Foo || Bar))()",
+        "(new new foo())()",
+        "new (new new foo())(bar)",
+        "(new foo).bar",
+        "(new foo)[bar]",
+        "(new foo).bar.baz",
+        "(new foo.bar).baz",
+        "(new foo).bar()",
+        "(new foo.bar).baz()",
+        "new (new foo).bar",
+        "new (new foo.bar).baz",
+        "(new new foo()).baz",
         "(2 + 3) ** 4",
         "2 ** (2 + 3)",
         "new (import(source))",
@@ -647,6 +658,11 @@ ruleTester.run("no-extra-parens", rule, {
         invalid("(foo()).bar", "foo().bar", "CallExpression"),
         invalid("(foo.bar()).baz", "foo.bar().baz", "CallExpression"),
         invalid("(foo\n.bar())\n.baz", "foo\n.bar()\n.baz", "CallExpression"),
+        invalid("(new foo()).bar", "new foo().bar", "NewExpression"),
+        invalid("(new foo()).bar()", "new foo().bar()", "NewExpression"),
+        invalid("(new foo(bar)).baz", "new foo(bar).baz", "NewExpression"),
+        invalid("(new foo.bar()).baz", "new foo.bar().baz", "NewExpression"),
+        invalid("(new foo.bar()).baz()", "new foo.bar().baz()", "NewExpression"),
 
         invalid("new (A)", "new A", "Identifier"),
         invalid("(new A())()", "new A()()", "NewExpression"),
diff --git a/tests/lib/rules/prefer-numeric-literals.js b/tests/lib/rules/prefer-numeric-literals.js
index e84017490..800047051 100644
--- a/tests/lib/rules/prefer-numeric-literals.js
+++ b/tests/lib/rules/prefer-numeric-literals.js
@@ -90,6 +90,68 @@ ruleTester.run("prefer-numeric-literals", rule, {
             code: "Number.parseInt('1️⃣3️⃣3️⃣7️⃣', 16);",
             output: null, // not fixed, javascript doesn't support emoji literals
             errors: [{ message: "Use hexadecimal literals instead of Number.parseInt()." }]
+        },
+
+        // Should not autofix if it would remove comments
+        {
+            code: "/* comment */Number.parseInt('11', 2);",
+            output: "/* comment */0b11;",
+            errors: 1
+        },
+        {
+            code: "Number/**/.parseInt('11', 2);",
+            output: null,
+            errors: 1
+        },
+        {
+            code: "Number//\n.parseInt('11', 2);",
+            output: null,
+            errors: 1
+        },
+        {
+            code: "Number./**/parseInt('11', 2);",
+            output: null,
+            errors: 1
+        },
+        {
+            code: "Number.parseInt(/**/'11', 2);",
+            output: null,
+            errors: 1
+        },
+        {
+            code: "Number.parseInt('11', /**/2);",
+            output: null,
+            errors: 1
+        },
+        {
+            code: "Number.parseInt('11', 2)/* comment */;",
+            output: "0b11/* comment */;",
+            errors: 1
+        },
+        {
+            code: "parseInt/**/('11', 2);",
+            output: null,
+            errors: 1
+        },
+        {
+            code: "parseInt(//\n'11', 2);",
+            output: null,
+            errors: 1
+        },
+        {
+            code: "parseInt('11'/**/, 2);",
+            output: null,
+            errors: 1
+        },
+        {
+            code: "parseInt('11', 2 /**/);",
+            output: null,
+            errors: 1
+        },
+        {
+            code: "parseInt('11', 2)//comment\n;",
+            output: "0b11//comment\n;",
+            errors: 1
         }
     ]
 });
diff --git a/tests/lib/shared/runtime-info.js b/tests/lib/shared/runtime-info.js
new file mode 100644
index 000000000..77ada8bc7
--- /dev/null
+++ b/tests/lib/shared/runtime-info.js
@@ -0,0 +1,216 @@
+/**
+ * @fileoverview Tests for RuntimeInfo util.
+ * @author Kai Cataldo
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const assert = require("chai").assert;
+const sinon = require("sinon");
+const spawn = require("cross-spawn");
+const { unIndent } = require("../_utils");
+const RuntimeInfo = require("../../../lib/shared/runtime-info");
+const log = require("../../../lib/shared/logging");
+const packageJson = require("../../../package.json");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Sets up spawn.sync() stub calls to return values and throw errors in the order in which they are given.
+ * @param {Function} stub - The stub to set up.
+ * @param {Array} returnVals - Values to be returned by subsequent stub calls.
+ * @returns {Function} The set up stub.
+ */
+function setupSpawnSyncStubReturnVals(stub, returnVals) {
+    let stubChain = stub;
+
+    for (const [i, val] of returnVals.entries()) {
+        const returnVal = val instanceof Error
+            ? { error: val }
+            : { stdout: val };
+
+        stubChain = stubChain.onCall(i).returns(returnVal);
+    }
+
+    return stubChain;
+}
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+const LOCAL_ESLINT_BIN_PATH = "/Users/username/code/project/node_modules/eslint/bin/eslint.js";
+const GLOBAL_ESLINT_BIN_PATH = "/usr/local/bin/npm/node_modules/eslint/bin/eslint.js";
+const NPM_BIN_PATH = "/usr/local/bin/npm";
+
+describe("RuntimeInfo", () => {
+    describe("environment()", () => {
+        let spawnSyncStub;
+        let logErrorStub;
+        let originalProcessArgv;
+        let spawnSyncStubArgs;
+
+        beforeEach(() => {
+            spawnSyncStub = sinon.stub(spawn, "sync");
+            logErrorStub = sinon.stub(log, "error");
+            originalProcessArgv = process.argv;
+            process.argv[1] = LOCAL_ESLINT_BIN_PATH;
+            spawnSyncStubArgs = [
+                "v12.8.0",
+                "6.11.3",
+                unIndent`
+                    {
+                        "name": "project",
+                        "version": "1.0.0",
+                        "dependencies": {
+                            "eslint": {
+                                "version": "6.3.0"
+                            }
+                        }
+                    }
+                `,
+                NPM_BIN_PATH,
+                unIndent`
+                    {
+                        "dependencies": {
+                            "eslint": {
+                                "version": "5.16.0",
+                                "from": "eslint",
+                                "resolved": "https://registry.npmjs.org/eslint/-/eslint-6.16.0.tgz"
+                            }
+                        }
+                    }
+                `,
+                NPM_BIN_PATH
+            ];
+        });
+
+        afterEach(() => {
+            spawnSyncStub.restore();
+            logErrorStub.restore();
+            process.argv = originalProcessArgv;
+        });
+
+
+        it("should return a string containing environment information when running local installation", () => {
+            setupSpawnSyncStubReturnVals(spawnSyncStub, spawnSyncStubArgs);
+
+            assert.strictEqual(
+                RuntimeInfo.environment(),
+                unIndent`
+                    Environment Info:
+
+                    Node version: v12.8.0
+                    npm version: v6.11.3
+                    Local ESLint version: v6.3.0 (Currently used)
+                    Global ESLint version: v5.16.0
+                `
+            );
+        });
+
+        it("should return a string containing environment information when running global installation", () => {
+            setupSpawnSyncStubReturnVals(spawnSyncStub, spawnSyncStubArgs);
+            process.argv[1] = GLOBAL_ESLINT_BIN_PATH;
+
+            assert.strictEqual(
+                RuntimeInfo.environment(),
+                unIndent`
+                    Environment Info:
+
+                    Node version: v12.8.0
+                    npm version: v6.11.3
+                    Local ESLint version: v6.3.0
+                    Global ESLint version: v5.16.0 (Currently used)
+                `
+            );
+        });
+
+        it("should return a string containing environment information when not installed locally", () => {
+            spawnSyncStubArgs.splice(2, 2, unIndent`
+                {
+                    "name": "project",
+                    "version": "1.0.0"
+                }
+            `);
+            setupSpawnSyncStubReturnVals(spawnSyncStub, spawnSyncStubArgs);
+            process.argv[1] = GLOBAL_ESLINT_BIN_PATH;
+
+            assert.strictEqual(
+                RuntimeInfo.environment(),
+                unIndent`
+                    Environment Info:
+
+                    Node version: v12.8.0
+                    npm version: v6.11.3
+                    Local ESLint version: Not found
+                    Global ESLint version: v5.16.0 (Currently used)
+                `
+            );
+        });
+
+        it("should return a string containing environment information when not installed globally", () => {
+            spawnSyncStubArgs[4] = "{}";
+            setupSpawnSyncStubReturnVals(spawnSyncStub, spawnSyncStubArgs);
+
+            assert.strictEqual(
+                RuntimeInfo.environment(),
+                unIndent`
+                    Environment Info:
+
+                    Node version: v12.8.0
+                    npm version: v6.11.3
+                    Local ESLint version: v6.3.0 (Currently used)
+                    Global ESLint version: Not found
+                `
+            );
+        });
+
+        it("log and throw an error when npm version can not be found", () => {
+            const expectedErr = new Error("npm can not be found");
+
+            spawnSyncStubArgs[1] = expectedErr;
+            setupSpawnSyncStubReturnVals(spawnSyncStub, spawnSyncStubArgs);
+
+            assert.throws(RuntimeInfo.environment, expectedErr);
+            assert.strictEqual(logErrorStub.args[0][0], "Error finding npm version running the command `npm --version`");
+        });
+
+        it("log and throw an error when npm binary path can not be found", () => {
+            const expectedErr = new Error("npm can not be found");
+
+            spawnSyncStubArgs[3] = expectedErr;
+            setupSpawnSyncStubReturnVals(spawnSyncStub, spawnSyncStubArgs);
+
+            assert.throws(RuntimeInfo.environment, expectedErr);
+            assert.strictEqual(logErrorStub.args[0][0], "Error finding npm binary path when running command `npm bin -g`");
+        });
+
+        it("log and throw an error when checking for local ESLint version when returned output of command is malformed", () => {
+            spawnSyncStubArgs[2] = "This is not JSON";
+            setupSpawnSyncStubReturnVals(spawnSyncStub, spawnSyncStubArgs);
+
+            assert.throws(RuntimeInfo.environment, "Unexpected token T in JSON at position 0");
+            assert.strictEqual(logErrorStub.args[0][0], "Error finding eslint version running the command `npm ls --depth=0 --json eslint`");
+        });
+
+        it("log and throw an error when checking for global ESLint version when returned output of command is malformed", () => {
+            spawnSyncStubArgs[4] = "This is not JSON";
+            setupSpawnSyncStubReturnVals(spawnSyncStub, spawnSyncStubArgs);
+
+            assert.throws(RuntimeInfo.environment, "Unexpected token T in JSON at position 0");
+            assert.strictEqual(logErrorStub.args[0][0], "Error finding eslint version running the command `npm ls --depth=0 --json eslint -g`");
+        });
+    });
+
+    describe("version()", () => {
+        it("should return the version of the package defined in package.json", () => {
+            assert.strictEqual(RuntimeInfo.version(), `v${packageJson.version}`);
+        });
+    });
+});