feat: handle vitest workspace configuration

packages/knip/fixtures/plugins/vitest8/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "@fixtures/vitest8",
+  "devDependencies": {
+    "vitest": "*"
+  }
+}

packages/knip/fixtures/plugins/vitest8/src/index.test.ts

@@ -0,0 +1,5 @@
+import { expect, test } from 'vitest';
+
+test('Unit A', () => {
+  expect(true).toBe(!false);
+});

packages/knip/fixtures/plugins/vitest8/vitest.config.ts

@@ -0,0 +1,20 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    workspace: [
+      {
+        test: {
+          name: 'integration',
+          setupFiles: './vitest.integration.setup.mjs',
+        },
+      },
+      {
+        test: {
+          globalSetup: './vitest.unit.setup.ts',
+          name: 'unit',
+        },
+      },
+    ],
+  },
+});

packages/knip/src/plugins/vitest/index.ts

@@ -45,7 +45,19 @@ const findConfigDependencies = (localConfig: ViteConfig, options: PluginOptions)
   const setupFiles = [testConfig.setupFiles ?? []].flat().map(specifier => ({ ...toDeferResolve(specifier), dir }));
   const globalSetup = [testConfig.globalSetup ?? []].flat().map(specifier => ({ ...toDeferResolve(specifier), dir }));
 
-  return [...[...environments, ...reporters, ...coverage].map(id => toDependency(id)), ...setupFiles, ...globalSetup];
+  const workspaceDependencies: Input[] = [];
+  if (testConfig.workspace !== undefined) {
+    for (const workspaceConfig of testConfig.workspace) {
+      workspaceDependencies.push(...findConfigDependencies(workspaceConfig, options));
+    }
+  }
+
+  return [
+    ...[...environments, ...reporters, ...coverage].map(id => toDependency(id)),
+    ...setupFiles,
+    ...globalSetup,
+    ...workspaceDependencies,
+  ];
 };
 
 const getConfigs = async (localConfig: ViteConfigOrFn | VitestWorkspaceConfig) => {

packages/knip/test/plugins/vitest8.test.ts

@@ -0,0 +1,26 @@
+import { test } from 'bun:test';
+import assert from 'node:assert/strict';
+import { main } from '../../src/index.js';
+import { resolve } from '../../src/util/path.js';
+import baseArguments from '../helpers/baseArguments.js';
+import baseCounters from '../helpers/baseCounters.js';
+
+const cwd = resolve('fixtures/plugins/vitest8');
+
+test('Find dependencies with Vitest plugin (8)', async () => {
+  const { counters, issues, report, rules } = await main({
+    ...baseArguments,
+    cwd,
+  });
+
+  assert(issues.unresolved['vitest.config.ts']['./vitest.integration.setup.mjs']);
+  assert(issues.unresolved['vitest.config.ts']['./vitest.unit.setup.ts']);
+
+  assert.deepEqual(counters, {
+    ...baseCounters,
+    unlisted: 0,
+    unresolved: 2,
+    processed: 3,
+    total: 3,
+  });
+});