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

Detect C# project-suffix dirs (Foo.Tests/, Foo.UnitTests/) and PascalCase
test dirs (Tests/, UnitTests/, IntegrationTests/) via case-insensitive
match; group test-file suggestions by language (JS, C#, Java, Go).

Keeps all suggestions commented-out — same opt-in model as today. Updates
SKILL.md Phase 0.5 inline generator to stay in sync with the TS module.

Refs #76

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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

@@ -95,6 +95,82 @@ 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");
+    });
+  });
+
   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 } from "node:fs";
 import { join } from "node:path";
 import { DEFAULT_IGNORE_PATTERNS } from "./ignore-filter.js";
 
@@ -12,23 +12,60 @@ const HEADER = `# .understandignore — patterns for files/dirs to exclude from
 #
 `;
 
-const DETECTABLE_DIRS = [
+// Directory names matched case-insensitively against the on-disk entry name.
-  { dir: "__tests__", pattern: "__tests__/" },
+// Includes JS/TS, Python, and PascalCase variants seen in C#/.NET projects.
-  { dir: "test", pattern: "test/" },
+const EXACT_DIR_NAMES = [
-  { dir: "tests", pattern: "tests/" },
+  "__tests__",
-  { dir: "fixtures", pattern: "fixtures/" },
+  "test",
-  { dir: "testdata", pattern: "testdata/" },
+  "tests",
-  { dir: "docs", pattern: "docs/" },
+  "fixtures",
-  { dir: "examples", pattern: "examples/" },
+  "testdata",
-  { dir: "scripts", pattern: "scripts/" },
+  "docs",
-  { dir: "migrations", pattern: "migrations/" },
+  "examples",
-  { dir: ".storybook", pattern: ".storybook/" },
+  "scripts",
+  "migrations",
+  ".storybook",
+  "unittests",
+  "integrationtests",
 ];
 
-const GENERIC_SUGGESTIONS = [
+// Directory-name suffixes matched case-insensitively. Covers C# / .NET
-  "*.test.*",
+// project-suffix conventions like Foo.Tests, Foo.UnitTests, Foo.IntegrationTests.
-  "*.spec.*",
+const SUFFIX_DIR_GLOBS = [
-  "*.snap",
+  ".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 +90,33 @@ 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: ReturnType<typeof readdirSync>;
+  try {
+    entries = readdirSync(projectRoot, { withFileTypes: true });
+  } 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 +139,8 @@ export function generateStarterIgnoreFile(projectRoot: string): string {
     sections.push("");
   }
 
-  // Section 2: detected directories
+  // Section 2: detected directories (case-insensitive + suffix-glob)
-  const detected: string[] = [];
+  const detected = detectDirectories(projectRoot);
-  for (const { dir, pattern } of DETECTABLE_DIRS) {
-    if (existsSync(join(projectRoot, dir))) {
-      detected.push(pattern);
-    }
-  }
-
   if (detected.length > 0) {
     sections.push("# --- Detected directories (uncomment to exclude) ---\n");
     for (const pattern of detected) {
@@ -91,10 +149,13 @@ 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) {
+  for (const group of TEST_PATTERN_GROUPS) {
-    sections.push(`# ${pattern}`);
+    sections.push(`# ${group.label}`);
+    for (const pattern of group.patterns) {
+      sections.push(`# ${pattern}`);
+    }
   }
   sections.push("");
 

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

@@ -217,10 +217,29 @@ Set up and verify the `.understandignore` file before scanning.
        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 exactDirs = ['__tests__','test','tests','fixtures','testdata','docs','examples','scripts','migrations','.storybook','unittests','integrationtests'];
-     const found = dirs.filter(d => fs.existsSync(path.join(root, d)));
+     const suffixDirs = ['.tests','.unittests','.integrationtests'];
+     const found = [];
+     try {
+       for (const ent of fs.readdirSync(root, { withFileTypes: true })) {
+         if (!ent.isDirectory()) continue;
+         const lower = ent.name.toLowerCase();
+         if (exactDirs.includes(lower) || suffixDirs.some(s => lower.endsWith(s))) {
+           found.push(ent.name);
+         }
+       }
+     } catch {}
      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 patternGroups = [
+       ['JS / TS', ['*.test.*','*.spec.*','*.snap']],
+       ['C# / .NET', ['**/*Tests.cs','**/*Test.cs','**/*Fixture.cs','**/*.Tests.csproj']],
+       ['Java / Kotlin', ['**/src/test/**','**/*Test.java','**/*IT.java','**/*Spec.kt']],
+       ['Go', ['**/*_test.go']],
+     ];
+     body += '# --- Test file patterns (uncomment to exclude) ---\n\n';
+     for (const [label, pats] of patternGroups) {
+       body += '# ' + label + '\n' + pats.map(p => '# ' + p).join('\n') + '\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);