test(#139): improve cmd/review-bot coverage from 44.6% to 49.3%

Add tests for previously uncovered paths:

- TestIsValidateError_Nil: isValidateError(nil, ...) returns false
- TestValidateURL_EmptyHost: URL with no hostname (https://) → code-2 error
- TestRunValidateURL_Success: success path (OK output + exit 0) via example.com
- TestMainSubprocess_MissingLLMBaseURL: --llm-base-url required for openai provider
- TestMainSubprocess_MissingAICoreCredentials: aicore creds required for provider=aicore
- TestMainSubprocess_ConflictingPersonaFlags: --persona and --persona-file are mutually exclusive
- TestMainSubprocess_DeprecatedGiteaURLEnv: GITEA_URL env var emits deprecation warning

All tests pass; no production code changes; dep check clean.

cmd/review-bot/main_test.go

@@ -1383,3 +1383,126 @@ func TestFetchPatterns_MultipleRepos(t *testing.T) {
 		t.Errorf("expected Elixir pipes content, got: %q", got)
 	}
 }
+
+// TestMainSubprocess_MissingLLMBaseURL confirms that --llm-base-url is required
+// when provider=openai (the default).
+func TestMainSubprocess_MissingLLMBaseURL(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot",
+			"--vcs-url", "https://gitea.example.com",
+			"--repo", "owner/repo",
+			"--pr", "1",
+			"--reviewer-token", "tok",
+			"--llm-model", "gpt-4",
+			// --llm-base-url and --llm-api-key intentionally omitted
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_MissingLLMBaseURL")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit when llm-base-url is missing")
+	}
+	if !strings.Contains(string(out), "llm-base-url") {
+		t.Errorf("expected error mentioning llm-base-url, got: %s", out)
+	}
+}
+
+// TestMainSubprocess_MissingAICoreCredentials confirms that aicore-specific credentials
+// are required when provider=aicore.
+func TestMainSubprocess_MissingAICoreCredentials(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot",
+			"--vcs-url", "https://gitea.example.com",
+			"--repo", "owner/repo",
+			"--pr", "1",
+			"--reviewer-token", "tok",
+			"--llm-model", "gpt-4",
+			"--llm-provider", "aicore",
+			// aicore-client-id, aicore-client-secret, aicore-auth-url, aicore-api-url omitted
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_MissingAICoreCredentials")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit when aicore credentials are missing")
+	}
+	if !strings.Contains(string(out), "AI Core credentials") {
+		t.Errorf("expected error about AI Core credentials, got: %s", out)
+	}
+}
+
+// TestMainSubprocess_ConflictingPersonaFlags confirms that --persona and --persona-file
+// cannot be used together.
+func TestMainSubprocess_ConflictingPersonaFlags(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot",
+			"--vcs-url", "https://gitea.example.com",
+			"--repo", "owner/repo",
+			"--pr", "1",
+			"--reviewer-token", "tok",
+			"--llm-base-url", "https://api.example.com",
+			"--llm-api-key", "key",
+			"--llm-model", "gpt-4",
+			"--persona", "security",
+			"--persona-file", "custom.json",
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_ConflictingPersonaFlags")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit with both --persona and --persona-file set")
+	}
+	if !strings.Contains(string(out), "mutually exclusive") {
+		t.Errorf("expected error about mutually exclusive flags, got: %s", out)
+	}
+}
+
+// TestMainSubprocess_DeprecatedGiteaURLEnv confirms that GITEA_URL env var still works
+// as a deprecated fallback for VCS_URL.
+func TestMainSubprocess_DeprecatedGiteaURLEnv(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		// Set required flags but omit --vcs-url; GITEA_URL should be picked up.
+		// The test will exit with an error after VCS init (no PR to fetch), but
+		// the deprecation warning must appear.
+		os.Args = []string{"review-bot",
+			// No --vcs-url: should fall back to GITEA_URL env var
+			"--repo", "owner/repo",
+			"--pr", "1",
+			"--reviewer-token", "tok",
+			"--llm-base-url", "https://api.example.com",
+			"--llm-api-key", "key",
+			"--llm-model", "gpt-4",
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_DeprecatedGiteaURLEnv")
+	// Inject GITEA_URL but NOT VCS_URL.
+	env := append(cleanEnv(),
+		"TEST_SUBPROCESS_MAIN=1",
+		"GITEA_URL=https://gitea.example.com",
+	)
+	cmd.Env = env
+	out, _ := cmd.CombinedOutput()
+	// The process will fail (no real server), but the deprecation warning must appear.
+	if !strings.Contains(string(out), "deprecated") {
+		t.Errorf("expected deprecation warning for GITEA_URL, got: %s", out)
+	}
+}

cmd/review-bot/validateurl_test.go

@@ -125,3 +125,60 @@ func TestRunValidateURL_WithCapture(t *testing.T) {
 		t.Errorf("expected error about https in stderr, got %q", errBuf.String())
 	}
 }
+
+// TestIsValidateError_Nil confirms that isValidateError returns false for a nil error.
+func TestIsValidateError_Nil(t *testing.T) {
+	var ve *validateError
+	if isValidateError(nil, &ve) {
+		t.Error("isValidateError(nil, ...) should return false")
+	}
+}
+
+// TestValidateURL_EmptyHost confirms that a URL with no hostname returns a code-2 error.
+func TestValidateURL_EmptyHost(t *testing.T) {
+	// "https://" parses fine but has no hostname.
+	err := validateURL("https://")
+	if err == nil {
+		t.Fatal("expected error for URL with no host, got nil")
+	}
+	var ve *validateError
+	if !isValidateError(err, &ve) {
+		t.Fatalf("expected *validateError, got %T: %v", err, err)
+	}
+	if ve.code != 2 {
+		t.Errorf("expected code 2, got %d (msg=%s)", ve.code, ve.message)
+	}
+	if !strings.Contains(ve.message, "no host") {
+		t.Errorf("expected 'no host' in error message, got %q", ve.message)
+	}
+}
+
+// TestRunValidateURL_Success confirms that a resolvable public URL prints "OK" and returns 0.
+// This test requires external DNS; it is skipped in environments without network access.
+func TestRunValidateURL_Success(t *testing.T) {
+	// Pre-check: validate that DNS is available before exercising the success path.
+	err := validateURL("https://example.com/")
+	if err != nil {
+		t.Skipf("skipping success-path test: DNS unavailable or example.com blocked (%v)", err)
+	}
+
+	var outBuf, errBuf bytes.Buffer
+	origOut, origErr := outWriter, errWriter
+	outWriter = &outBuf
+	errWriter = &errBuf
+	defer func() {
+		outWriter = origOut
+		errWriter = origErr
+	}()
+
+	code := runValidateURL([]string{"https://example.com/"})
+	if code != 0 {
+		t.Errorf("expected exit code 0 for safe URL, got %d (stderr: %s)", code, errBuf.String())
+	}
+	if !strings.Contains(outBuf.String(), "OK:") {
+		t.Errorf("expected 'OK:' in stdout, got %q", outBuf.String())
+	}
+	if errBuf.Len() != 0 {
+		t.Errorf("expected no stderr for safe URL, got %q", errBuf.String())
+	}
+}