fix: rule tester ignore irrelevant test case properties (#18235)

* fix: ignore irrelevant test case properties for the duplication check

* fix: only ignore top-level test case properties

* chore: test case merge fixes

lib/rule-tester/rule-tester.js

@@ -136,6 +136,15 @@ const suggestionObjectParameters = new Set([
 ]);
 const friendlySuggestionObjectParameterList = `[${[...suggestionObjectParameters].map(key => `'${key}'`).join(", ")}]`;
 
+/*
+ * Ignored test case properties when checking for test case duplicates.
+ */
+const duplicationIgnoredParameters = new Set([
+ "name",
+ "errors",
+ "output"
+]);
+
 const forbiddenMethods = [
  "applyInlineConfig",
  "applyLanguageOptions",
@@ -848,7 +857,7 @@ class RuleTester {
 
  /**
  * Check if this test case is a duplicate of one we have seen before.
- * @param {Object} item test case object
+ * @param {string|Object} item test case object
  * @param {Set<string>} seenTestCases set of serialized test cases we have seen so far (managed by this function)
  * @returns {void}
  * @private
@@ -863,7 +872,14 @@ class RuleTester {
  return;
  }
 
- const serializedTestCase = stringify(item);
+ const normalizedItem = typeof item === "string" ? { code: item } : item;
+ const serializedTestCase = stringify(normalizedItem, {
+ replacer(key, value) {
+
+ // "this" is the currently stringified object --> only ignore top-level properties
+ return (normalizedItem !== this || !duplicationIgnoredParameters.has(key)) ? value : void 0;
+ }
+ });
 
  assert(
  !seenTestCases.has(serializedTestCase),

tests/lib/rule-tester/rule-tester.js

@@ -3148,7 +3148,7 @@ describe("RuleTester", () => {
  }
  }, {
  valid: ["foo", "foo"],
- invalid: [{ code: "foo", errors: [{ message: "foo bar" }] }]
+ invalid: []
  });
  }, "detected duplicate test case");
  });
@@ -3162,10 +3162,69 @@ describe("RuleTester", () => {
  }
  }, {
  valid: [{ code: "foo" }, { code: "foo" }],
- invalid: [{ code: "foo", errors: [{ message: "foo bar" }] }]
+ invalid: []
+ });
+ }, "detected duplicate test case");
+ });
+
+ it("throws with string and object test cases", () => {
+ assert.throws(() => {
+ ruleTester.run("foo", {
+ meta: {},
+ create() {
+ return {};
+ }
+ }, {
+ valid: ["foo", { code: "foo" }],
+ invalid: []
+ });
+ }, "detected duplicate test case");
+ });
+
+ it("ignores the name property", () => {
+ assert.throws(() => {
+ ruleTester.run("foo", {
+ meta: {},
+ create() {
+ return {};
+ }
+ }, {
+ valid: [{ code: "foo" }, { name: "bar", code: "foo" }],
+ invalid: []
  });
  }, "detected duplicate test case");
  });
+
+ it("does not ignore top level test case properties nested in other test case properties", () => {
+ ruleTester.run("foo", {
+ meta: { schema: [{ type: "object" }] },
+ create() {
+ return {};
+ }
+ }, {
+ valid: [{ options: [{ name: "foo" }], name: "foo", code: "same" }, { options: [{ name: "bar" }], name: "bar", code: "same" }],
+ invalid: []
+ });
+ });
+
+ it("does not throw an error for defining the same test case in different run calls", () => {
+ const rule = {
+ meta: {},
+ create() {
+ return {};
+ }
+ };
+
+ ruleTester.run("foo", rule, {
+ valid: ["foo"],
+ invalid: []
+ });
+
+ ruleTester.run("foo", rule, {
+ valid: ["foo"],
+ invalid: []
+ });
+ });
  });
 
  describe("invalid test cases", () => {
@@ -3328,6 +3387,48 @@ describe("RuleTester", () => {
  ]
  });
  });
+
+ it("detects duplicate test cases even if the error matchers differ", () => {
+ assert.throws(() => {
+ ruleTester.run("foo", {
+ meta: { schema: false },
+ create(context) {
+ return {
+ VariableDeclaration(node) {
+ context.report(node, "foo bar");
+ }
+ };
+ }
+ }, {
+ valid: [],
+ invalid: [
+ { code: "const x = 123;", errors: [{ message: "foo bar" }] },
+ { code: "const x = 123;", errors: 1 }
+ ]
+ });
+ }, "detected duplicate test case");
+ });
+
+ it("detects duplicate test cases even if the presence of the output property differs", () => {
+ assert.throws(() => {
+ ruleTester.run("foo", {
+ meta: { schema: false },
+ create(context) {
+ return {
+ VariableDeclaration(node) {
+ context.report(node, "foo bar");
+ }
+ };
+ }
+ }, {
+ valid: [],
+ invalid: [
+ { code: "const x = 123;", errors: 1 },
+ { code: "const x = 123;", errors: 1, output: null }
+ ]
+ });
+ }, "detected duplicate test case");
+ });
  });
  });
 

tests/lib/rules/accessor-pairs.js

@@ -1047,10 +1047,10 @@ ruleTester.run("accessor-pairs", rule, {
 
  // Full location tests
  {
- code: "var o = { get a() {} };",
+ code: "var o = { get b() {} };",
  options: [{ setWithoutGet: true, getWithoutSet: true }],
  errors: [{
- message: "Setter is not present for getter 'a'.",
+ message: "Setter is not present for getter 'b'.",
  type: "Property",
  line: 1,
  column: 11,
@@ -1831,11 +1831,11 @@ ruleTester.run("accessor-pairs", rule, {
  }]
  },
  {
- code: "class A { static get a() {} };",
+ code: "class A { static get b() {} };",
  options: [{ setWithoutGet: true, getWithoutSet: true, enforceForClassMembers: true }],
  languageOptions: { ecmaVersion: 6 },
  errors: [{
- message: "Setter is not present for class static getter 'a'.",
+ message: "Setter is not present for class static getter 'b'.",
  type: "MethodDefinition",
  line: 1,
  column: 11,

tests/lib/rules/array-bracket-newline.js

@@ -761,25 +761,6 @@ ruleTester.run("array-bracket-newline", rule, {
  }
  ]
  },
- {
- code: "var foo = [\n1\n];",
- output: "var foo = [1];",
- options: ["never"],
- errors: [
- {
- messageId: "unexpectedOpeningLinebreak",
- type: "ArrayExpression",
- line: 1,
- column: 11
- },
- {
- messageId: "unexpectedClosingLinebreak",
- type: "ArrayExpression",
- line: 3,
- column: 1
- }
- ]
- },
  {
  code: "var foo = [ /* any comment */\n1, 2\n];",
  output: "var foo = [ /* any comment */\n1, 2];",

tests/lib/rules/array-callback-return.js

@@ -273,7 +273,6 @@ ruleTester.run("array-callback-return", rule, {
  { code: "foo.forEach(function(x) { if (a == b) {return x;}})", options: checkForEachOptions, errors: [{ messageId: "expectedNoReturnValue", data: { name: "function", arrayMethodName: "Array.prototype.forEach" } }] },
  { code: "foo.forEach(function(x) { if (a == b) {return undefined;}})", options: checkForEachOptions, errors: [{ messageId: "expectedNoReturnValue", data: { name: "function", arrayMethodName: "Array.prototype.forEach" } }] },
  { code: "foo.forEach(function bar(x) { return x;})", options: checkForEachOptions, errors: [{ messageId: "expectedNoReturnValue", data: { name: "function 'bar'", arrayMethodName: "Array.prototype.forEach" } }] },
- { code: "foo.forEach(function bar(x) { return x;})", options: checkForEachOptions, errors: ["Array.prototype.forEach() expects no useless return value from function 'bar'."] },
  { code: "foo.bar().forEach(function bar(x) { return x;})", options: checkForEachOptions, errors: [{ messageId: "expectedNoReturnValue", data: { name: "function 'bar'", arrayMethodName: "Array.prototype.forEach" } }] },
  { code: "[\"foo\",\"bar\"].forEach(function bar(x) { return x;})", options: checkForEachOptions, errors: [{ messageId: "expectedNoReturnValue", data: { name: "function 'bar'", arrayMethodName: "Array.prototype.forEach" } }] },
  { code: "foo.forEach((x) => { return x;})", options: checkForEachOptions, languageOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue", data: { name: "arrow function", arrayMethodName: "Array.prototype.forEach" } }] },

tests/lib/rules/constructor-super.js

@@ -225,10 +225,6 @@ ruleTester.run("constructor-super", rule, {
  },
 
  // nested execution scope.
- {
- code: "class A extends B { constructor() { class C extends D { constructor() { super(); } } } }",
- errors: [{ messageId: "missingAll", type: "MethodDefinition" }]
- },
  {
  code: "class A extends B { constructor() { var c = class extends D { constructor() { super(); } } } }",
  errors: [{ messageId: "missingAll", type: "MethodDefinition" }]

tests/lib/rules/no-object-constructor.js

@@ -193,7 +193,6 @@ ruleTester.run("no-object-constructor", rule, {
  ...[
 
  // No semicolon required before `({})` because ASI does not occur
- { code: "Object()" },
  {
  code: `
  {}

tests/lib/rules/no-unused-vars.js

@@ -1512,21 +1512,16 @@ ruleTester.run("no-unused-vars", rule, {
  // https://github.com/eslint/eslint/issues/10982
  {
  code: "var a = function() { a(); };",
- errors: [assignedError("a")]
+ errors: [{ ...assignedError("a"), line: 1, column: 5 }]
  },
  {
  code: "var a = function(){ return function() { a(); } };",
- errors: [assignedError("a")]
- },
- {
- code: "const a = () => { a(); };",
- languageOptions: { ecmaVersion: 2015 },
- errors: [assignedError("a")]
+ errors: [{ ...assignedError("a"), line: 1, column: 5 }]
  },
  {
  code: "const a = () => () => { a(); };",
  languageOptions: { ecmaVersion: 2015 },
- errors: [assignedError("a")]
+ errors: [{ ...assignedError("a"), line: 1, column: 7 }]
  },
  {
  code: `let myArray = [1,2,3,4].filter((x) => x == 0);
@@ -1539,24 +1534,11 @@ ruleTester.run("no-unused-vars", rule, {
  languageOptions: { ecmaVersion: 2015 },
  errors: [{ ...assignedError("a"), line: 1, column: 14 }]
  },
- {
- code: "var a = function() { a(); };",
- errors: [{ ...assignedError("a"), line: 1, column: 5 }]
- },
- {
- code: "var a = function(){ return function() { a(); } };",
- errors: [{ ...assignedError("a"), line: 1, column: 5 }]
- },
  {
  code: "const a = () => { a(); };",
  languageOptions: { ecmaVersion: 2015 },
  errors: [{ ...assignedError("a"), line: 1, column: 7 }]
  },
- {
- code: "const a = () => () => { a(); };",
- languageOptions: { ecmaVersion: 2015 },
- errors: [{ ...assignedError("a"), line: 1, column: 7 }]
- },
 
  // https://github.com/eslint/eslint/issues/14324
  {

tests/lib/rules/no-useless-backreference.js

@@ -162,9 +162,9 @@ ruleTester.run("no-useless-backreference", rule, {
  }]
  },
  {
- code: String.raw`/\k<foo>(?<foo>a)/`,
+ code: String.raw`/\k<foo>(?<foo>bar)/`,
  errors: [{
- message: String.raw`Backreference '\k<foo>' will be ignored. It references group '(?<foo>a)' which appears later in the pattern.`,
+ message: String.raw`Backreference '\k<foo>' will be ignored. It references group '(?<foo>bar)' which appears later in the pattern.`,
  type: "Literal"
  }]
  },