feat(rule-tester): allow to create empty tests (#7467)

* feat(rule-tester): allow to create empty tests * feat(rule-tester): add tests with empty valid and invalid suites * fix(rule-tester): improve tests with empty rule tester suites
typescript-eslint · Sep 3, 2023 · 654b35d · 654b35d
1 parent 7012279
commit 654b35d
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Showing 2 changed files with 79 additions and 22 deletions.
diff --git a/packages/rule-tester/src/RuleTester.ts b/packages/rule-tester/src/RuleTester.ts
@@ -395,33 +395,37 @@ export class RuleTester extends TestFramework {
      * one of the templates above.
      */
     constructor.describe(ruleName, () => {
-      constructor.describe('valid', () => {
-        normalizedTests.valid.forEach(valid => {
-          const testName = ((): string => {
-            if (valid.name == null || valid.name.length === 0) {
-              return valid.code;
-            }
-            return valid.name;
-          })();
-          constructor[getTestMethod(valid)](sanitize(testName), () => {
-            this.#testValidTemplate(ruleName, rule, valid);
+      if (normalizedTests.valid.length) {
+        constructor.describe('valid', () => {
+          normalizedTests.valid.forEach(valid => {
+            const testName = ((): string => {
+              if (valid.name == null || valid.name.length === 0) {
+                return valid.code;
+              }
+              return valid.name;
+            })();
+            constructor[getTestMethod(valid)](sanitize(testName), () => {
+              this.#testValidTemplate(ruleName, rule, valid);
+            });
           });
         });
-      });
+      }
 
-      constructor.describe('invalid', () => {
-        normalizedTests.invalid.forEach(invalid => {
-          const name = ((): string => {
-            if (invalid.name == null || invalid.name.length === 0) {
-              return invalid.code;
-            }
-            return invalid.name;
-          })();
-          constructor[getTestMethod(invalid)](sanitize(name), () => {
-            this.#testInvalidTemplate(ruleName, rule, invalid);
+      if (normalizedTests.invalid.length) {
+        constructor.describe('invalid', () => {
+          normalizedTests.invalid.forEach(invalid => {
+            const name = ((): string => {
+              if (invalid.name == null || invalid.name.length === 0) {
+                return invalid.code;
+              }
+              return invalid.name;
+            })();
+            constructor[getTestMethod(invalid)](sanitize(name), () => {
+              this.#testInvalidTemplate(ruleName, rule, invalid);
+            });
           });
         });
-      });
+      }
     });
   }
 

diff --git a/packages/rule-tester/tests/RuleTester.test.ts b/packages/rule-tester/tests/RuleTester.test.ts
@@ -819,6 +819,59 @@ describe('RuleTester', () => {
         expect(mockedDescribeSkip.mock.calls).toHaveLength(0);
         // expect(mockedIt.mock.lastCall).toMatchInlineSnapshot(`undefined`);
       });
+
+      it('does not call describe with valid if no valid tests are provided', () => {
+        const ruleTester = new RuleTester();
+
+        ruleTester.run('my-rule', NOOP_RULE, {
+          valid: [],
+          invalid: [
+            {
+              code: 'invalid',
+              errors: [{ messageId: 'error' }],
+            },
+          ],
+        });
+
+        expect(mockedDescribe.mock.calls).toMatchInlineSnapshot(`
+          [
+            [
+              "my-rule",
+              [Function],
+            ],
+            [
+              "invalid",
+              [Function],
+            ],
+          ]
+        `);
+      });
+
+      it('does not call describe with invalid if no invalid tests are provided', () => {
+        const ruleTester = new RuleTester();
+
+        ruleTester.run('my-rule', NOOP_RULE, {
+          valid: [
+            {
+              code: 'valid',
+            },
+          ],
+          invalid: [],
+        });
+
+        expect(mockedDescribe.mock.calls).toMatchInlineSnapshot(`
+          [
+            [
+              "my-rule",
+              [Function],
+            ],
+            [
+              "valid",
+              [Function],
+            ],
+          ]
+        `);
+      });
     });
   });
 });