address feedback and add more tests

packages/utils/src/eslint-utils/rule-tester/RuleTester.ts

@@ -9,6 +9,7 @@ import type { DependencyConstraint } from './dependencyConstraints';
 import { satisfiesAllDependencyConstraints } from './dependencyConstraints';
 
 const TS_ESLINT_PARSER = '@typescript-eslint/parser';
+const ERROR_MESSAGE = `Do not set the parser at the test level unless you want to use a parser other than ${TS_ESLINT_PARSER}`;
 
 type RuleTesterConfig = Omit<TSESLint.RuleTesterConfig, 'parser'> & {
   parser: typeof TS_ESLINT_PARSER;
@@ -109,8 +110,6 @@ class RuleTester extends TSESLint.RuleTester {
     rule: TSESLint.RuleModule<TMessageIds, TOptions>,
     testsReadonly: RunTests<TMessageIds, TOptions>,
   ): void {
-    const errorMessage = `Do not set the parser at the test level unless you want to use a parser other than ${TS_ESLINT_PARSER}`;
-
     const tests = {
       // standardize the valid tests as objects
       valid: testsReadonly.valid.map(test => {
@@ -124,6 +123,18 @@ class RuleTester extends TSESLint.RuleTester {
       invalid: testsReadonly.invalid,
     };
 
+    // convenience iterator to make it easy to loop all tests without a concat
+    const allTestsIterator = {
+      *[Symbol.iterator](): Generator<ValidTestCase<TOptions>, void, unknown> {
+        for (const test of tests.valid) {
+          yield test;
+        }
+        for (const test of tests.invalid) {
+          yield test;
+        }
+      },
+    };
+
     /*
     Automatically add a filename to the tests to enable type-aware tests to "just work".
     This saves users having to verbosely and manually add the filename to every
@@ -139,7 +150,7 @@ class RuleTester extends TSESLint.RuleTester {
       test: T,
     ): T => {
       if (test.parser === TS_ESLINT_PARSER) {
-        throw new Error(errorMessage);
+        throw new Error(ERROR_MESSAGE);
       }
       if (!test.filename) {
         return {
@@ -153,12 +164,7 @@ class RuleTester extends TSESLint.RuleTester {
     tests.invalid = tests.invalid.map(addFilename);
 
     const hasOnly = ((): boolean => {
-      for (const test of tests.valid) {
-        if (test.only) {
-          return true;
-        }
-      }
-      for (const test of tests.invalid) {
+      for (const test of allTestsIterator) {
         if (test.only) {
           return true;
         }
@@ -172,15 +178,7 @@ class RuleTester extends TSESLint.RuleTester {
       Automatically skip tests that don't satisfy the dependency constraints.
       */
       const hasConstraints = ((): boolean => {
-        for (const test of tests.valid) {
-          if (
-            test.dependencyConstraints &&
-            Object.keys(test.dependencyConstraints).length > 0
-          ) {
-            return true;
-          }
-        }
-        for (const test of tests.invalid) {
+        for (const test of allTestsIterator) {
           if (
             test.dependencyConstraints &&
             Object.keys(test.dependencyConstraints).length > 0
@@ -191,6 +189,7 @@ class RuleTester extends TSESLint.RuleTester {
         return false;
       })();
       if (hasConstraints) {
+        // The `only: boolean` test property was only added in ESLint v7.29.0.
         if (semver.satisfies(eslintVersion, '>=7.29.0')) {
           /*
           Mark all satisfactory tests as `only: true`, and all other tests as
@@ -225,10 +224,7 @@ class RuleTester extends TSESLint.RuleTester {
           tests.valid = tests.valid.map(maybeMarkAsOnly);
           tests.invalid = tests.invalid.map(maybeMarkAsOnly);
         } else {
-          /*
-          The `only: boolean` test property was only added in ESLint v7.29.0.
-          on older versions we just fallback to raw filtering like savages
-          */
+          // On older versions we just fallback to raw array filtering like SAVAGES
           tests.valid = tests.valid.filter(test =>
             satisfiesAllDependencyConstraints(test.dependencyConstraints),
           );

packages/utils/src/eslint-utils/rule-tester/dependencyConstraints.ts

@@ -1,26 +1,20 @@
 import * as semver from 'semver';
 
 interface SemverVersionConstraint {
-  readonly type: 'semver';
   readonly range: string;
   readonly options?: Parameters<typeof semver.satisfies>[2];
 }
-interface AtLeastVersionConstraint {
-  readonly type: 'at-least';
-  readonly version:
-    | `${number}`
-    | `${number}.${number}`
-    | `${number}.${number}.${number}`
-    | `${number}.${number}.${number}-${string}`;
-}
+type AtLeastVersionConstraint =
+  | `${number}`
+  | `${number}.${number}`
+  | `${number}.${number}.${number}`
+  | `${number}.${number}.${number}-${string}`;
 type VersionConstraint = SemverVersionConstraint | AtLeastVersionConstraint;
 interface DependencyConstraint {
   /**
    * Passing a string for the value is shorthand for the 'at-least' constraint
    */
-  readonly [packageName: string]:
-    | VersionConstraint
-    | AtLeastVersionConstraint['version'];
+  readonly [packageName: string]: VersionConstraint;
 }
 
 const BASE_SATISFIES_OPTIONS: semver.RangeOptions = {
@@ -31,27 +25,19 @@ function satisfiesDependencyConstraint(
   packageName: string,
   constraintIn: DependencyConstraint[string],
 ): boolean {
-  const constraint: VersionConstraint =
+  const constraint: SemverVersionConstraint =
     typeof constraintIn === 'string'
       ? {
-          type: 'at-least',
-          version: constraintIn,
+          range: `>=${constraintIn}`,
         }
       : constraintIn;
 
-  const satisfiesArguments: [string, SemverVersionConstraint['options']] =
-    constraint.type === 'at-least'
-      ? [`>=${constraint.version}`, BASE_SATISFIES_OPTIONS]
-      : [
-          constraint.range,
-          typeof constraint.options === 'object'
-            ? { ...BASE_SATISFIES_OPTIONS, ...constraint.options }
-            : constraint.options,
-        ];
-
   return semver.satisfies(
     (require(`${packageName}/package.json`) as { version: string }).version,
-    ...satisfiesArguments,
+    constraint.range,
+    typeof constraint.options === 'object'
+      ? { ...BASE_SATISFIES_OPTIONS, ...constraint.options }
+      : constraint.options,
   );
 }