1 files changed, 147 insertions, 0 deletions
diff --git a/packages/cli/src/ui/themes/theme.test.ts b/packages/cli/src/ui/themes/theme.test.ts
new file mode 100644
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+++ b/packages/cli/src/ui/themes/theme.test.ts
@@ -0,0 +1,147 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import * as themeModule from './theme.js';
+import { themeManager } from './theme-manager.js';
+
+const { validateCustomTheme } = themeModule;
+type CustomTheme = themeModule.CustomTheme;
+
+describe('validateCustomTheme', () => {
+  const validTheme: CustomTheme = {
+    type: 'custom',
+    name: 'My Custom Theme',
+    Background: '#FFFFFF',
+    Foreground: '#000000',
+    LightBlue: '#ADD8E6',
+    AccentBlue: '#0000FF',
+    AccentPurple: '#800080',
+    AccentCyan: '#00FFFF',
+    AccentGreen: '#008000',
+    AccentYellow: '#FFFF00',
+    AccentRed: '#FF0000',
+    DiffAdded: '#00FF00',
+    DiffRemoved: '#FF0000',
+    Comment: '#808080',
+    Gray: '#808080',
+  };
+
+  it('should return isValid: true for a valid theme', () => {
+    const result = validateCustomTheme(validTheme);
+    expect(result.isValid).toBe(true);
+    expect(result.error).toBeUndefined();
+  });
+
+  it('should return isValid: false for a theme with a missing required field', () => {
+    const invalidTheme = {
+      ...validTheme,
+      name: undefined as unknown as string,
+    };
+    const result = validateCustomTheme(invalidTheme);
+    expect(result.isValid).toBe(false);
+    expect(result.error).toBe('Missing required field: name');
+  });
+
+  it('should return isValid: false for a theme with an invalid color format', () => {
+    const invalidTheme = { ...validTheme, Background: 'not-a-color' };
+    const result = validateCustomTheme(invalidTheme);
+    expect(result.isValid).toBe(false);
+    expect(result.error).toBe(
+      'Invalid color format for Background: not-a-color',
+    );
+  });
+
+  it('should return isValid: false for a theme with an invalid name', () => {
+    const invalidTheme = { ...validTheme, name: ' ' };
+    const result = validateCustomTheme(invalidTheme);
+    expect(result.isValid).toBe(false);
+    expect(result.error).toBe('Invalid theme name:  ');
+  });
+
+  it('should return isValid: true for a theme missing optional DiffAdded and DiffRemoved colors', () => {
+    const legacyTheme: Partial<CustomTheme> = { ...validTheme };
+    delete legacyTheme.DiffAdded;
+    delete legacyTheme.DiffRemoved;
+    const result = validateCustomTheme(legacyTheme);
+    expect(result.isValid).toBe(true);
+    expect(result.error).toBeUndefined();
+  });
+
+  it('should return a warning if DiffAdded and DiffRemoved are missing', () => {
+    const legacyTheme: Partial<CustomTheme> = { ...validTheme };
+    delete legacyTheme.DiffAdded;
+    delete legacyTheme.DiffRemoved;
+    const result = validateCustomTheme(legacyTheme);
+    expect(result.isValid).toBe(true);
+    expect(result.warning).toBe('Missing field(s) DiffAdded, DiffRemoved');
+  });
+
+  it('should return a warning if only DiffRemoved is missing', () => {
+    const legacyTheme: Partial<CustomTheme> = { ...validTheme };
+    delete legacyTheme.DiffRemoved;
+    const result = validateCustomTheme(legacyTheme);
+    expect(result.isValid).toBe(true);
+    expect(result.warning).toBe('Missing field(s) DiffRemoved');
+  });
+
+  it('should return isValid: false for a theme with an invalid DiffAdded color', () => {
+    const invalidTheme = { ...validTheme, DiffAdded: 'invalid' };
+    const result = validateCustomTheme(invalidTheme);
+    expect(result.isValid).toBe(false);
+    expect(result.error).toBe('Invalid color format for DiffAdded: invalid');
+  });
+
+  it('should return isValid: false for a theme with an invalid DiffRemoved color', () => {
+    const invalidTheme = { ...validTheme, DiffRemoved: 'invalid' };
+    const result = validateCustomTheme(invalidTheme);
+    expect(result.isValid).toBe(false);
+    expect(result.error).toBe('Invalid color format for DiffRemoved: invalid');
+  });
+
+  it('should return isValid: false for a theme with a very long name', () => {
+    const invalidTheme = { ...validTheme, name: 'a'.repeat(51) };
+    const result = validateCustomTheme(invalidTheme);
+    expect(result.isValid).toBe(false);
+    expect(result.error).toBe(`Invalid theme name: ${'a'.repeat(51)}`);
+  });
+});
+
+describe('themeManager.loadCustomThemes', () => {
+  const baseTheme: Omit<CustomTheme, 'DiffAdded' | 'DiffRemoved'> & {
+    DiffAdded?: string;
+    DiffRemoved?: string;
+  } = {
+    type: 'custom',
+    name: 'Test Theme',
+    Background: '#FFF',
+    Foreground: '#000',
+    LightBlue: '#ADD8E6',
+    AccentBlue: '#00F',
+    AccentPurple: '#808',
+    AccentCyan: '#0FF',
+    AccentGreen: '#080',
+    AccentYellow: '#FF0',
+    AccentRed: '#F00',
+    Comment: '#888',
+    Gray: '#888',
+  };
+
+  it('should use values from DEFAULT_THEME when DiffAdded and DiffRemoved are not provided', () => {
+    const { darkTheme } = themeModule;
+    const legacyTheme: Partial<CustomTheme> = { ...baseTheme };
+    delete legacyTheme.DiffAdded;
+    delete legacyTheme.DiffRemoved;
+
+    themeManager.loadCustomThemes({ 'Legacy Custom Theme': legacyTheme });
+    const result = themeManager.getTheme('Legacy Custom Theme')!;
+
+    expect(result.colors.DiffAdded).toBe(darkTheme.DiffAdded);
+    expect(result.colors.DiffRemoved).toBe(darkTheme.DiffRemoved);
+    expect(result.colors.AccentBlue).toBe(legacyTheme.AccentBlue);
+    expect(result.name).toBe(legacyTheme.name);
+  });
+});