chore: install openagent opencode

Signed-off-by: Dmytro Stanchiev <git@dmytros.dev>

.opencode/context/core/standards/test-coverage.md

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+<!-- Context: standards/tests | Priority: critical | Version: 2.0 | Updated: 2025-01-21 -->
+
+# Testing Standards
+
+## Quick Reference
+
+**Golden Rule**: If you can't test it easily, refactor it
+
+**AAA Pattern**: Arrange → Act → Assert
+
+**Test** (✅ DO):
+- Happy path, edge cases, error cases
+- Business logic, public APIs
+
+**Don't Test** (❌ DON'T):
+- Third-party libraries, framework internals
+- Simple getters/setters, private details
+
+**Coverage**: Critical (100%), High (90%+), Medium (80%+)
+
+---
+
+## Principles
+
+**Test behavior, not implementation**: Focus on what code does, not how
+**Keep tests simple**: One assertion per test, clear names, minimal setup
+**Independent tests**: No shared state, run in any order
+**Fast and reliable**: Quick execution, no flaky tests, deterministic
+
+## Test Structure (AAA Pattern)
+
+```javascript
+test('calculateTotal returns sum of item prices', () => {
+  // Arrange - Set up test data
+  const items = [{ price: 10 }, { price: 20 }, { price: 30 }];
+  
+  // Act - Execute code
+  const result = calculateTotal(items);
+  
+  // Assert - Verify result
+  expect(result).toBe(60);
+});
+```
+
+## What to Test
+
+### ✅ DO Test
+- Happy path (normal usage)
+- Edge cases (boundaries, empty, null, undefined)
+- Error cases (invalid input, failures)
+- Business logic (core functionality)
+- Public APIs (exported functions)
+
+### ❌ DON'T Test
+- Third-party libraries
+- Framework internals
+- Simple getters/setters
+- Private implementation details
+
+## Coverage Goals
+
+1. **Critical**: Business logic, data transformations (100%)
+2. **High**: Public APIs, user-facing features (90%+)
+3. **Medium**: Utilities, helpers (80%+)
+4. **Low**: Simple wrappers, configs (optional)
+
+## Testing Pure Functions
+
+```javascript
+function add(a, b) { return a + b; }
+
+test('add returns sum', () => {
+  expect(add(2, 3)).toBe(5);
+  expect(add(-1, 1)).toBe(0);
+  expect(add(0, 0)).toBe(0);
+});
+```
+
+## Testing with Dependencies
+
+```javascript
+// Testable with dependency injection
+function createUserService(database) {
+  return {
+    getUser: (id) => database.findById('users', id)
+  };
+}
+
+// Test with mock
+test('getUser retrieves from database', () => {
+  const mockDb = {
+    findById: jest.fn().mockReturnValue({ id: 1, name: 'John' })
+  };
+  
+  const service = createUserService(mockDb);
+  const user = service.getUser(1);
+  
+  expect(mockDb.findById).toHaveBeenCalledWith('users', 1);
+  expect(user).toEqual({ id: 1, name: 'John' });
+});
+```
+
+## Test Naming
+
+```javascript
+// ✅ Good: Descriptive, clear expectation
+test('calculateDiscount returns 10% off for premium users', () => {});
+test('validateEmail returns false for invalid format', () => {});
+test('createUser throws error when email exists', () => {});
+
+// ❌ Bad: Vague, unclear
+test('it works', () => {});
+test('test user', () => {});
+```
+
+## Best Practices
+
+✅ Test one thing per test
+✅ Use descriptive test names
+✅ Keep tests independent
+✅ Mock external dependencies
+✅ Test edge cases and errors
+✅ Make tests readable
+✅ Run tests frequently
+✅ Fix failing tests immediately
+
+**Golden Rule**: If you can't test it easily, refactor it.