fix: detect class/function type more reliably (#882)

* fix: detect class/function type more reliably

* remove unused import

Author: FloEdelmann

src/utils/types.ts

@@ -1,6 +1,5 @@
 import { TSESTree } from '@typescript-eslint/utils'
 import type ts from 'typescript'
-import { require } from './require'
 
 export enum UtilName {
   vi = 'vi',
@@ -86,23 +85,8 @@ interface TypeAssertionChain<
 }
 
 export function isClassOrFunctionType(type: ts.Type): boolean {
-  if (type.getCallSignatures().length > 0) return true
-
-  const ts = require('typescript')
-
   return (
-    type
-      .getSymbol()
-      ?.getDeclarations()
-      ?.some(
-        (declaration) =>
-          ts.isArrowFunction(declaration) ||
-          ts.isClassDeclaration(declaration) ||
-          ts.isClassExpression(declaration) ||
-          ts.isFunctionDeclaration(declaration) ||
-          ts.isFunctionExpression(declaration) ||
-          ts.isMethodDeclaration(declaration) ||
-          ts.isFunctionTypeNode(declaration),
-      ) ?? false
+    type.getCallSignatures().length > 0 ||
+    type.getConstructSignatures().length > 0
   )
 }

tests/fixture/myFunction.ts

@@ -1 +1,7 @@
 export function myFunction() {}
+
+type ValidatorFn = () => boolean
+export const validatorFunction: ValidatorFn = () => true
+
+class Foo {}
+export const foo = new Foo()

tests/prefer-describe-function-title.test.ts

@@ -101,6 +101,18 @@ ruleTester.run(rule.name, rule, {
         },
       },
     },
+    {
+      code: `
+        import { foo } from "./myFunction"
+        describe("foo", () => {})
+      `,
+      filename: 'myFunction.test.ts',
+      settings: {
+        vitest: {
+          typecheck: true,
+        },
+      },
+    },
   ],
   invalid: [
     {
@@ -185,5 +197,28 @@ ruleTester.run(rule.name, rule, {
         },
       },
     },
+    {
+      code: `
+        import { validatorFunction } from "./myFunction"
+        describe("validatorFunction", () => {})
+      `,
+      errors: [
+        {
+          column: 18,
+          line: 3,
+          messageId: 'preferFunction',
+        },
+      ],
+      filename: 'myFunction.test.ts',
+      output: `
+        import { validatorFunction } from "./myFunction"
+        describe(validatorFunction, () => {})
+      `,
+      settings: {
+        vitest: {
+          typecheck: true,
+        },
+      },
+    },
   ],
 })

tests/valid-title.test.ts

@@ -106,6 +106,18 @@ ruleTester.run(rule.name, rule, {
       });`,
       settings: { vitest: { typecheck: true } },
     },
+    {
+      code: `
+        import { validatorFunction } from "./myFunction"
+        describe(validatorFunction, () => {
+          test('item', () => {
+            expect(0).toBe(0)
+          })
+        })
+      `,
+      filename: 'myFunction.test.ts',
+      settings: { vitest: { typecheck: true } },
+    },
   ],
   invalid: [
     {