feat(core): broaden .understandignore starter for C#/Java/Go test patterns

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

@@ -95,6 +95,106 @@ describe("generateStarterIgnoreFile", () => {
     expect(content).not.toContain("# fixtures/");
   });
 
+  describe("multi-language test directory detection", () => {
+    it("suggests PascalCase Tests/ via case-insensitive match", () => {
+      mkdirSync(join(testDir, "Tests"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      // On-disk casing is preserved in the suggestion.
+      expect(content).toContain("# Tests/");
+    });
+
+    it("suggests UnitTests/ via case-insensitive match", () => {
+      mkdirSync(join(testDir, "UnitTests"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# UnitTests/");
+    });
+
+    it("suggests IntegrationTests/ via case-insensitive match", () => {
+      mkdirSync(join(testDir, "IntegrationTests"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# IntegrationTests/");
+    });
+
+    it("suggests C# project-suffix .Tests/ directories", () => {
+      mkdirSync(join(testDir, "MyApp.Tests"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# MyApp.Tests/");
+    });
+
+    it("suggests C# project-suffix .UnitTests/ directories", () => {
+      mkdirSync(join(testDir, "MyApp.UnitTests"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# MyApp.UnitTests/");
+    });
+
+    it("suggests C# project-suffix .IntegrationTests/ directories", () => {
+      mkdirSync(join(testDir, "MyApp.IntegrationTests"), { recursive: true });
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# MyApp.IntegrationTests/");
+    });
+
+    it("ignores files that happen to share a detected name", () => {
+      writeFileSync(join(testDir, "tests"), "not a directory");
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).not.toContain("# tests/");
+    });
+  });
+
+  describe("language-grouped test file patterns", () => {
+    it("includes C# / .NET test file patterns", () => {
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# C# / .NET");
+      expect(content).toContain("# **/*Tests.cs");
+      expect(content).toContain("# **/*Test.cs");
+      expect(content).toContain("# **/*Fixture.cs");
+      expect(content).toContain("# **/*.Tests.csproj");
+    });
+
+    it("includes Java / Kotlin test file patterns", () => {
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# Java / Kotlin");
+      expect(content).toContain("# **/*Test.java");
+      expect(content).toContain("# **/*IT.java");
+      expect(content).toContain("# **/*Spec.kt");
+      expect(content).toContain("# **/src/test/**");
+    });
+
+    it("includes Go test file patterns", () => {
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).toContain("# Go");
+      expect(content).toContain("# **/*_test.go");
+    });
+
+    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", () => {
+      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");
+      expect(jsIdx).toBeGreaterThan(-1);
+      expect(csIdx).toBeGreaterThan(jsIdx);
+      expect(javaIdx).toBeGreaterThan(csIdx);
+      expect(goIdx).toBeGreaterThan(javaIdx);
+    });
+
+    it("keeps all suggestions commented even with no detected dirs and no .gitignore", () => {
+      const content = generateStarterIgnoreFile(testDir);
+      const uncommented = content.split("\n").filter((l) => l.trim() && !l.startsWith("#"));
+      expect(uncommented).toHaveLength(0);
+    });
+
+    it("ignores a file whose name would match a suffix-glob", () => {
+      writeFileSync(join(testDir, "MyApp.Tests"), "not a directory");
+      const content = generateStarterIgnoreFile(testDir);
+      expect(content).not.toContain("# MyApp.Tests/");
+    });
+  });
+
   describe(".gitignore integration", () => {
     it("includes .gitignore patterns not covered by defaults", () => {
       writeFileSync(join(testDir, ".gitignore"), ".env\nsecrets/\n*.pyc\n");

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

@@ -1,4 +1,4 @@
-import { existsSync, readFileSync } from "node:fs";
+import { existsSync, readdirSync, readFileSync, type Dirent } from "node:fs";
 import { join } from "node:path";
 import { DEFAULT_IGNORE_PATTERNS } from "./ignore-filter.js";
 
@@ -12,23 +12,65 @@ const HEADER = `# .understandignore — patterns for files/dirs to exclude from
 #
 `;
 
-const DETECTABLE_DIRS = [
-  { dir: "__tests__", pattern: "__tests__/" },
-  { dir: "test", pattern: "test/" },
-  { dir: "tests", pattern: "tests/" },
-  { dir: "fixtures", pattern: "fixtures/" },
-  { dir: "testdata", pattern: "testdata/" },
-  { dir: "docs", pattern: "docs/" },
-  { dir: "examples", pattern: "examples/" },
-  { dir: "scripts", pattern: "scripts/" },
-  { dir: "migrations", pattern: "migrations/" },
-  { dir: ".storybook", pattern: ".storybook/" },
+// 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.
+const EXACT_DIR_NAMES = [
+  "__tests__",
+  "test",
+  "tests",
+  "fixtures",
+  "testdata",
+  "docs",
+  "examples",
+  "scripts",
+  "migrations",
+  ".storybook",
+  "unittests",
+  "integrationtests",
 ];
 
-const GENERIC_SUGGESTIONS = [
-  "*.test.*",
-  "*.spec.*",
-  "*.snap",
+// Directory-name suffixes matched case-insensitively via String.endsWith.
+// Primarily intended for C# / .NET project-suffix conventions like Foo.Tests,
+// Foo.UnitTests, Foo.IntegrationTests, but note the match is unanchored —
+// e.g. a hypothetical `.storybook.tests` would also match. Suggestions stay
+// commented-out so the user reviews before activating.
+const SUFFIX_DIR_GLOBS = [
+  ".tests",
+  ".unittests",
+  ".integrationtests",
+];
+
+// Test file patterns grouped by language. Emitted as commented suggestions
+// with a sub-header per group.
+const TEST_PATTERN_GROUPS: Array<{ label: string; patterns: string[] }> = [
+  {
+    label: "JS / TS",
+    patterns: ["*.test.*", "*.spec.*", "*.snap"],
+  },
+  {
+    label: "C# / .NET",
+    patterns: [
+      "**/*Tests.cs",
+      "**/*Test.cs",
+      "**/*Fixture.cs",
+      "**/*.Tests.csproj",
+    ],
+  },
+  {
+    label: "Java / Kotlin",
+    patterns: [
+      "**/src/test/**",
+      "**/*Test.java",
+      "**/*IT.java",
+      "**/*Spec.kt",
+    ],
+  },
+  {
+    label: "Go",
+    patterns: ["**/*_test.go"],
+  },
 ];
 
 /**
@@ -53,6 +95,33 @@ function isCoveredByDefaults(pattern: string): boolean {
   return DEFAULT_IGNORE_PATTERNS.some((d) => normalize(d) === normalized);
 }
 
+/**
+ * Detects directories under projectRoot that match either an exact name
+ * (case-insensitive) in EXACT_DIR_NAMES or end with one of SUFFIX_DIR_GLOBS.
+ * Returns patterns using the directory's actual on-disk casing.
+ */
+function detectDirectories(projectRoot: string): string[] {
+  let entries: Dirent[];
+  try {
+    entries = readdirSync(projectRoot, { withFileTypes: true, encoding: "utf-8" });
+  } catch {
+    return [];
+  }
+  const matches: string[] = [];
+  for (const entry of entries) {
+    if (!entry.isDirectory()) continue;
+    const lower = entry.name.toLowerCase();
+    if (EXACT_DIR_NAMES.includes(lower)) {
+      matches.push(`${entry.name}/`);
+      continue;
+    }
+    if (SUFFIX_DIR_GLOBS.some((suffix) => lower.endsWith(suffix))) {
+      matches.push(`${entry.name}/`);
+    }
+  }
+  return matches;
+}
+
 /**
  * Generates a starter .understandignore file content by scanning the project
  * for common directories and reading .gitignore patterns.
@@ -75,14 +144,8 @@ export function generateStarterIgnoreFile(projectRoot: string): string {
     sections.push("");
   }
 
-  // Section 2: detected directories
-  const detected: string[] = [];
-  for (const { dir, pattern } of DETECTABLE_DIRS) {
-    if (existsSync(join(projectRoot, dir))) {
-      detected.push(pattern);
-    }
-  }
-
+  // Section 2: detected directories (case-insensitive + suffix-glob)
+  const detected = detectDirectories(projectRoot);
   if (detected.length > 0) {
     sections.push("# --- Detected directories (uncomment to exclude) ---\n");
     for (const pattern of detected) {
@@ -91,10 +154,13 @@ export function generateStarterIgnoreFile(projectRoot: string): string {
     sections.push("");
   }
 
-  // Section 3: generic test patterns
+  // Section 3: test file patterns, grouped by language
   sections.push("# --- Test file patterns (uncomment to exclude) ---\n");
-  for (const pattern of GENERIC_SUGGESTIONS) {
-    sections.push(`# ${pattern}`);
+  for (const group of TEST_PATTERN_GROUPS) {
+    sections.push(`# ${group.label}`);
+    for (const pattern of group.patterns) {
+      sections.push(`# ${pattern}`);
+    }
   }
   sections.push("");
 

understand-anything-plugin/skills/understand/SKILL.md

@@ -200,31 +200,9 @@ Determine whether to run a full analysis or incremental update.
 Set up and verify the `.understandignore` file before scanning.
 
 1. Check if `$PROJECT_ROOT/.understand-anything/.understandignore` exists.
-2. **If it does NOT exist**, generate a starter file:
-   - Run the following Node.js one-liner in `$PROJECT_ROOT` (reads `.gitignore` and deduplicates against built-in defaults):
+2. **If it does NOT exist**, generate a starter file by invoking the bundled script (delegates to `generateStarterIgnoreFile` in `@understand-anything/core`, which reads `.gitignore`, deduplicates against built-in defaults, and emits language-grouped test-file suggestions). Pass `$PLUGIN_ROOT` via the env so the script doesn't have to re-derive it from its own path (which breaks for copied skill installs):
      ```bash
-     node -e "
-     const fs = require('fs');
-     const path = require('path');
-     const root = process.cwd();
-     const defaults = ['node_modules/','node_modules','.git/','vendor/','venv/','.venv/','__pycache__/','dist/','dist','build/','build','out/','coverage/','coverage','.next/','.cache/','.turbo/','target/','obj/','*.lock','package-lock.json','yarn.lock','pnpm-lock.yaml','*.png','*.jpg','*.jpeg','*.gif','*.svg','*.ico','*.woff','*.woff2','*.ttf','*.eot','*.mp3','*.mp4','*.pdf','*.zip','*.tar','*.gz','*.min.js','*.min.css','*.map','*.generated.*','.idea/','.vscode/','LICENSE','.gitignore','.editorconfig','.prettierrc','.eslintrc*','*.log'];
-     const norm = p => p.replace(/\/+$/, '');
-     const defaultSet = new Set(defaults.map(norm));
-     const header = '# .understandignore — patterns for files/dirs to exclude from analysis\n# Syntax: same as .gitignore (globs, # comments, ! negation, trailing / for dirs)\n# Lines below are suggestions — uncomment to activate.\n# Use ! prefix to force-include something excluded by defaults.\n#\n# Built-in defaults (always excluded unless negated):\n#   node_modules/, .git/, dist/, build/, obj/, *.lock, *.min.js, etc.\n#\n';
-     let body = '';
-     const gitignorePath = path.join(root, '.gitignore');
-     if (fs.existsSync(gitignorePath)) {
-       const gi = fs.readFileSync(gitignorePath, 'utf-8').split('\n').map(l => l.trim()).filter(l => l && !l.startsWith('#')).filter(p => !defaultSet.has(norm(p)));
-       if (gi.length) { body += '# --- From .gitignore (uncomment to exclude) ---\n\n' + gi.map(p => '# ' + p).join('\n') + '\n\n'; }
-     }
-     const dirs = ['__tests__','test','tests','fixtures','testdata','docs','examples','scripts','migrations','.storybook'];
-     const found = dirs.filter(d => fs.existsSync(path.join(root, d)));
-     if (found.length) { body += '# --- Detected directories (uncomment to exclude) ---\n\n' + found.map(d => '# ' + d + '/').join('\n') + '\n\n'; }
-     body += '# --- Test file patterns (uncomment to exclude) ---\n\n# *.test.*\n# *.spec.*\n# *.snap\n';
-     const outDir = path.join(root, '.understand-anything');
-     if (!fs.existsSync(outDir)) fs.mkdirSync(outDir, { recursive: true });
-     fs.writeFileSync(path.join(outDir, '.understandignore'), header + body);
-     "
+     PLUGIN_ROOT="$PLUGIN_ROOT" node <SKILL_DIR>/generate-ignore.mjs $PROJECT_ROOT
      ```
    - Report to the user:
      > Generated `.understand-anything/.understandignore` with suggested exclusions based on your project structure. Please review it and uncomment any patterns you'd like to exclude from analysis. When ready, confirm to continue.

understand-anything-plugin/skills/understand/generate-ignore.mjs

@@ -0,0 +1,66 @@
+#!/usr/bin/env node
+/**
+ * generate-ignore.mjs
+ *
+ * Writes a starter `.understand-anything/.understandignore` for the target
+ * project by delegating to `generateStarterIgnoreFile` in
+ * `@understand-anything/core`. Invoked from SKILL.md Phase 0.5; replaces the
+ * inline `node -e "…"` block that previously duplicated the generator logic.
+ *
+ * Usage:
+ *   node generate-ignore.mjs <projectRoot>
+ *
+ * Behaviour:
+ *   - Exits 0 with a stderr notice if the target file already exists.
+ *   - Creates `<projectRoot>/.understand-anything/` if missing.
+ *   - Emits a one-line stderr summary on success.
+ *
+ * Mirrors the @understand-anything/core resolution dance used by
+ * scan-project.mjs: workspace-linked package first, plugin-cache dist fallback.
+ *
+ * Plugin root resolution: prefer $PLUGIN_ROOT from the environment (set by
+ * SKILL.md Phase 0 via its multi-candidate search) over the
+ * `resolve(__dirname, '../..')` heuristic. The relative path breaks when
+ * `skills/understand/` is copied into a runtime skills directory whose
+ * parent is not the plugin checkout.
+ */
+
+import { createRequire } from 'node:module';
+import { dirname, join, resolve } from 'node:path';
+import { fileURLToPath, pathToFileURL } from 'node:url';
+import { existsSync, mkdirSync, writeFileSync } from 'node:fs';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+function resolvePluginRoot() {
+  const envRoot = process.env.PLUGIN_ROOT;
+  if (envRoot && existsSync(join(envRoot, 'package.json'))) {
+    return envRoot;
+  }
+  return resolve(__dirname, '../..');
+}
+
+const pluginRoot = resolvePluginRoot();
+const require = createRequire(resolve(pluginRoot, 'package.json'));
+
+let core;
+try {
+  core = await import(pathToFileURL(require.resolve('@understand-anything/core')).href);
+} catch {
+  core = await import(pathToFileURL(resolve(pluginRoot, 'packages/core/dist/index.js')).href);
+}
+
+const { generateStarterIgnoreFile } = core;
+
+const projectRoot = resolve(process.argv[2] ?? process.cwd());
+const outDir = join(projectRoot, '.understand-anything');
+const outPath = join(outDir, '.understandignore');
+
+if (existsSync(outPath)) {
+  console.error(`generate-ignore: ${outPath} already exists — skipping`);
+  process.exit(0);
+}
+
+if (!existsSync(outDir)) mkdirSync(outDir, { recursive: true });
+writeFileSync(outPath, generateStarterIgnoreFile(projectRoot));
+console.error(`generate-ignore: wrote ${outPath}`);