feat(core): broaden .understandignore starter — C++ test/benchmark patterns

understand-anything-plugin/packages/core/src/__tests__/ignore-generator.test.ts

@@ -138,6 +138,30 @@ describe("generateStarterIgnoreFile", () => {
       const content = generateStarterIgnoreFile(testDir);
       expect(content).not.toContain("# tests/");
     });
+
+    it("suggests singular unittest/ (mongo-style)", () => {
+      mkdirSync(join(testDir, "unittest"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# unittest/");
+    });
+
+    it("suggests benchmark/ directories", () => {
+      mkdirSync(join(testDir, "benchmark"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# benchmark/");
+    });
+
+    it("suggests benchmarks/ directories", () => {
+      mkdirSync(join(testDir, "benchmarks"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# benchmarks/");
+    });
+
+    it("suggests bench/ directories", () => {
+      mkdirSync(join(testDir, "bench"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# bench/");
+    });
   });
 
   describe("language-grouped test file patterns", () => {
@@ -165,21 +189,42 @@ describe("generateStarterIgnoreFile", () => {
       expect(content).toContain("# **/*_test.go");
     });
 
+    it("includes C++ test file patterns", () => {
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# C++");
+      // gtest-style snake_case suffix (abseil / protobuf / grpc / mongo).
+      expect(content).toContain("# **/*_test.cc");
+      expect(content).toContain("# **/*_test.cpp");
+      expect(content).toContain("# **/*_test.cxx");
+      // PascalCase suffix (folly, LLVM unittests).
+      expect(content).toContain("# **/*Test.cc");
+      expect(content).toContain("# **/*Test.cpp");
+      // Chromium / protobuf / Electron idiom.
+      expect(content).toContain("# **/*_unittest.cc");
+      expect(content).toContain("# **/*_unittest.cpp");
+      expect(content).toContain("# **/*_browsertest.cc");
+      // Benchmarks frequently co-located with source.
+      expect(content).toContain("# **/*_benchmark.cc");
+      expect(content).toContain("# **/*Benchmark.cpp");
+    });
+
     it("groups patterns under the JS / TS sub-header", () => {
       const content = generateStarterIgnoreFile(testDir);
       expect(content).toContain("# JS / TS");
     });
 
-    it("emits language groups in stable order: JS, C#, Java, Go", () => {
+    it("emits language groups in stable order: JS, C#, Java, Go, C++", () => {
       const content = generateStarterIgnoreFile(testDir);
       const jsIdx = content.indexOf("# JS / TS");
       const csIdx = content.indexOf("# C# / .NET");
       const javaIdx = content.indexOf("# Java / Kotlin");
       const goIdx = content.indexOf("# Go");
+      const cppIdx = content.indexOf("# C++");
       expect(jsIdx).toBeGreaterThan(-1);
       expect(csIdx).toBeGreaterThan(jsIdx);
       expect(javaIdx).toBeGreaterThan(csIdx);
       expect(goIdx).toBeGreaterThan(javaIdx);
+      expect(cppIdx).toBeGreaterThan(goIdx);
     });
 
     it("keeps all suggestions commented even with no detected dirs and no .gitignore", () => {

understand-anything-plugin/packages/core/src/ignore-generator.ts

@@ -14,8 +14,9 @@ const HEADER = `# .understandignore — patterns for files/dirs to exclude from
 
 // Directory names matched case-insensitively against the on-disk entry name.
 // Mixes ecosystem conventions: __tests__ (JS), test/tests (multi), testdata
-// (Go), .storybook (JS), and PascalCase variants (UnitTests/IntegrationTests)
-// commonly seen in C#/.NET projects.
+// (Go), .storybook (JS), PascalCase variants (UnitTests/IntegrationTests)
+// commonly seen in C#/.NET projects, and benchmark dirs (bench/benchmarks)
+// idiomatic to large C++ projects (LLVM, abseil, bitcoin, Catch2).
 const EXACT_DIR_NAMES = [
   "__tests__",
   "test",
@@ -28,7 +29,11 @@ const EXACT_DIR_NAMES = [
   "migrations",
   ".storybook",
   "unittests",
+  "unittest",
   "integrationtests",
+  "bench",
+  "benchmark",
+  "benchmarks",
 ];
 
 // Directory-name suffixes matched case-insensitively via String.endsWith.
@@ -71,6 +76,24 @@ const TEST_PATTERN_GROUPS: Array<{ label: string; patterns: string[] }> = [
     label: "Go",
     patterns: ["**/*_test.go"],
   },
+  {
+    // Many C++ projects (abseil, Chromium, protobuf) interleave test files
+    // with source rather than using a dedicated test/ dir — so file-pattern
+    // exclusions matter more here than for languages where tests cluster.
+    label: "C++",
+    patterns: [
+      "**/*_test.cc",
+      "**/*_test.cpp",
+      "**/*_test.cxx",
+      "**/*Test.cc",
+      "**/*Test.cpp",
+      "**/*_unittest.cc",
+      "**/*_unittest.cpp",
+      "**/*_browsertest.cc",
+      "**/*_benchmark.cc",
+      "**/*Benchmark.cpp",
+    ],
+  },
 ];
 
 /**