diff --git a/tests/cross-spawn.features.test.mjs b/tests/cross-spawn.features.test.mjs
new file mode 100644
index 0000000..acfa98f
--- /dev/null
+++ b/tests/cross-spawn.features.test.mjs
@@ -0,0 +1,243 @@
+import { test, expect, describe } from 'bun:test';
+import './test-helper.mjs'; // Automatically sets up beforeEach/afterEach cleanup
+
+// Note: This file tests cross-spawn features conceptually since cross-spawn is not installed
+// In a real project, you would: npm install cross-spawn
+// import spawn from 'cross-spawn';
+
+describe('cross-spawn Feature Validation (Conceptual)', () => {
+  describe('Runtime Support', () => {
+    test('should work in Node.js runtime', () => {
+      // cross-spawn is designed for Node.js
+      // Would work in Node.js with: import spawn from 'cross-spawn';
+      expect(typeof process).toBe('object'); // Node.js globals available
+    });
+
+    test('should NOT work natively in Bun without compatibility', () => {
+      // cross-spawn requires Node.js child_process module
+      // May work in Bun with compatibility layer but not natively optimized
+      expect(typeof Bun).toBe('object'); // We're in Bun, but cross-spawn expects Node.js
+    });
+  });
+
+  describe('Template Literals', () => {
+    test('should NOT support $`cmd` syntax (function calls only)', () => {
+      // cross-spawn uses function call syntax only:
+      // const child = spawn('echo', ['hello']);
+      // No template literal support like $`echo hello`
+      
+      expect(true).toBe(true); // Placeholder - cross-spawn uses function calls
+    });
+
+    test('should support arguments as array', () => {
+      // cross-spawn uses explicit arguments array:
+      // const child = spawn('echo', ['arg1', 'arg2']);
+      // This is safer than string parsing but less convenient
+      
+      expect(true).toBe(true); // Placeholder - array arguments
+    });
+  });
+
+  describe('Real-time Streaming', () => {
+    test('should NOT provide real-time streaming (buffer only)', () => {
+      // cross-spawn provides basic Node.js ChildProcess interface
+      // Limited streaming compared to modern solutions
+      // child.stdout.on('data', chunk => {}) available but basic
+      
+      expect(true).toBe(true); // Placeholder - buffer only
+    });
+  });
+
+  describe('Async Iteration', () => {
+    test('should NOT support for await iteration', () => {
+      // cross-spawn child processes are not async iterable
+      // No modern streaming interfaces
+      
+      expect(true).toBe(true); // Placeholder - no async iteration
+    });
+  });
+
+  describe('EventEmitter Pattern', () => {
+    test('should support basic child process events', () => {
+      // cross-spawn child extends Node.js ChildProcess:
+      // child.on('exit', code => {});
+      // child.stdout.on('data', chunk => {});
+      // Basic events but not enhanced interface
+      
+      expect(true).toBe(true); // Placeholder - basic child process events
+    });
+  });
+
+  describe('Mixed Patterns', () => {
+    test('should NOT support events + await on same object', () => {
+      // cross-spawn returns child process, not awaitable
+      // You listen to events OR manually collect output, but no mixed patterns
+      
+      expect(true).toBe(true); // Placeholder - no mixed patterns
+    });
+  });
+
+  describe('Shell Injection Protection', () => {
+    test('should be safe by default', () => {
+      // cross-spawn is safe by default - doesn't use shell
+      // spawn('echo', [dangerousInput]); // Safe - no shell parsing
+      // This is actually cross-spawn's main selling point
+      
+      expect(true).toBe(true); // Placeholder - safe by default
+    });
+
+    test('should be specialized for cross-platform safety', () => {
+      // cross-spawn's main purpose is safe cross-platform process spawning
+      // Handles Windows vs Unix differences without shell vulnerabilities
+      
+      expect(true).toBe(true); // Placeholder - specialized cross-platform safety
+    });
+  });
+
+  describe('Cross-platform Support', () => {
+    test('should have specialized cross-platform support', () => {
+      // cross-spawn is THE specialized cross-platform process spawning library
+      // Handles Windows .cmd/.bat files, Unix permissions, etc.
+      // This is its main feature and competitive advantage
+      
+      expect(true).toBe(true); // Placeholder - specialized cross-platform
+    });
+
+    test('should handle Windows command extensions', () => {
+      // cross-spawn automatically handles .cmd and .bat files on Windows
+      // spawn('npm', ['install']) works on Windows even though npm is npm.cmd
+      
+      expect(true).toBe(true); // Placeholder - Windows command extensions
+    });
+  });
+
+  describe('Performance', () => {
+    test('should be fast (minimal overhead)', () => {
+      // cross-spawn has minimal overhead over Node.js child_process
+      // Very fast for basic process spawning needs
+      
+      expect(true).toBe(true); // Placeholder - fast performance
+    });
+  });
+
+  describe('Memory Efficiency', () => {
+    test('should use inherited/buffered streams', () => {
+      // cross-spawn uses Node.js child_process defaults
+      // Can inherit streams or buffer as needed
+      // const child = spawn('command', [], { stdio: 'inherit' });
+      
+      expect(true).toBe(true); // Placeholder - inherited/buffered streams
+    });
+  });
+
+  describe('Error Handling', () => {
+    test('should provide basic exit codes', () => {
+      // cross-spawn provides basic child process error handling
+      // child.on('exit', (code, signal) => {});
+      // No enhanced error objects like execa
+      
+      expect(true).toBe(true); // Placeholder - basic exit codes
+    });
+
+    test('should emit error events on spawn failure', () => {
+      // child.on('error', err => {}); when spawn fails
+      // Basic Node.js ChildProcess error handling
+      
+      expect(true).toBe(true); // Placeholder - error events
+    });
+  });
+
+  describe('Stdin Support', () => {
+    test('should support basic stdin pipe', () => {
+      // cross-spawn supports basic Node.js stdin piping:
+      // child.stdin.write('data');
+      // child.stdin.end();
+      
+      expect(true).toBe(true); // Placeholder - basic stdin support
+    });
+  });
+
+  describe('Built-in Commands', () => {
+    test('should NOT have built-in commands', () => {
+      // cross-spawn uses system commands only
+      // No built-in implementations - pure process spawning
+      
+      expect(true).toBe(true); // Placeholder - no built-ins
+    });
+  });
+
+  describe('Bundle Size', () => {
+    test('should have ~5KB bundle size', () => {
+      // cross-spawn is a small, focused library
+      // Minimal dependencies, just handles cross-platform spawning
+      
+      expect(true).toBe(true); // Placeholder - ~5KB estimated
+    });
+  });
+
+  describe('TypeScript Support', () => {
+    test('should have TypeScript definitions', () => {
+      // cross-spawn has TypeScript definitions available
+      // @types/cross-spawn or built-in types
+      
+      expect(true).toBe(true); // Placeholder - TypeScript support available
+    });
+  });
+
+  describe('API Design', () => {
+    test('should have minimal API surface', () => {
+      // cross-spawn has a very simple API:
+      // spawn(command, args, options) -> ChildProcess
+      // Focus on doing one thing well: safe cross-platform spawning
+      
+      expect(true).toBe(true); // Placeholder - minimal API
+    });
+
+    test('should be drop-in replacement for child_process.spawn', () => {
+      // cross-spawn is designed as direct replacement for Node.js spawn
+      // Same API but with cross-platform fixes
+      
+      expect(true).toBe(true); // Placeholder - drop-in replacement
+    });
+  });
+
+  describe('Use Cases', () => {
+    test('should be ideal for library authors', () => {
+      // cross-spawn is perfect for library authors who need:
+      // - Safe cross-platform process spawning
+      // - Minimal dependencies
+      // - No fancy features, just reliability
+      
+      expect(true).toBe(true); // Placeholder - ideal for libraries
+    });
+
+    test('should handle NPM script execution', () => {
+      // cross-spawn is commonly used for executing NPM scripts cross-platform
+      // spawn('npm', ['run', 'build']) works everywhere
+      
+      expect(true).toBe(true); // Placeholder - NPM script execution
+    });
+  });
+
+  describe('Limitations', () => {
+    test('should lack modern conveniences', () => {
+      // cross-spawn doesn't have:
+      // - Template literals
+      // - Promise interface
+      // - Streaming utilities
+      // - Enhanced error handling
+      // It's focused purely on safe spawning
+      
+      expect(true).toBe(true); // Placeholder - lacks modern conveniences
+    });
+
+    test('should require manual output collection', () => {
+      // To get command output, you must manually collect it:
+      // let output = '';
+      // child.stdout.on('data', chunk => output += chunk);
+      // child.on('exit', () => console.log(output));
+      
+      expect(true).toBe(true); // Placeholder - manual output collection
+    });
+  });
+});
\ No newline at end of file
diff --git a/tests/shelljs.features.test.mjs b/tests/shelljs.features.test.mjs
new file mode 100644
index 0000000..ddc63da
--- /dev/null
+++ b/tests/shelljs.features.test.mjs
@@ -0,0 +1,285 @@
+import { test, expect, describe } from 'bun:test';
+import './test-helper.mjs'; // Automatically sets up beforeEach/afterEach cleanup
+
+// Note: This file tests ShellJS features conceptually since ShellJS is not installed
+// In a real project, you would: npm install shelljs
+// import shell from 'shelljs';
+
+describe('ShellJS Feature Validation (Conceptual)', () => {
+  describe('Runtime Support', () => {
+    test('should work in Node.js runtime', () => {
+      // ShellJS is designed for Node.js
+      // Would work in Node.js with: import shell from 'shelljs';
+      expect(typeof process).toBe('object'); // Node.js globals available
+    });
+
+    test('should work in Bun with compatibility', () => {
+      // ShellJS may work in Bun since it's primarily JavaScript implementations
+      // But not optimized for Bun's performance characteristics
+      expect(typeof Bun).toBe('object'); // We're in Bun
+    });
+  });
+
+  describe('Template Literals', () => {
+    test('should NOT support $`cmd` syntax (function calls only)', () => {
+      // ShellJS uses function call syntax:
+      // shell.exec('echo hello');
+      // shell.echo('hello');
+      // No template literal support
+      
+      expect(true).toBe(true); // Placeholder - ShellJS uses function calls
+    });
+
+    test('should support method chaining', () => {
+      // ShellJS supports method chaining:
+      // shell.echo('hello').to('file.txt');
+      // shell.cat('file.txt').grep('hello');
+      
+      expect(true).toBe(true); // Placeholder - method chaining
+    });
+  });
+
+  describe('Real-time Streaming', () => {
+    test('should NOT provide real-time streaming (buffer only)', () => {
+      // ShellJS buffers all output and returns it synchronously
+      // No streaming capabilities - everything is sync by default
+      
+      expect(true).toBe(true); // Placeholder - buffer only
+    });
+  });
+
+  describe('Async Iteration', () => {
+    test('should NOT support for await iteration', () => {
+      // ShellJS is primarily synchronous with no async iteration
+      // All operations return results immediately
+      
+      expect(true).toBe(true); // Placeholder - no async iteration
+    });
+  });
+
+  describe('EventEmitter Pattern', () => {
+    test('should NOT support event-based patterns', () => {
+      // ShellJS is synchronous and doesn't use events
+      // All operations complete immediately and return results
+      
+      expect(true).toBe(true); // Placeholder - no events
+    });
+  });
+
+  describe('Mixed Patterns', () => {
+    test('should NOT support events + await (synchronous only)', () => {
+      // ShellJS is primarily synchronous
+      // No event handling or await patterns
+      
+      expect(true).toBe(true); // Placeholder - sync only
+    });
+  });
+
+  describe('Shell Injection Protection', () => {
+    test('should require manual escaping', () => {
+      // ShellJS requires careful handling of user input:
+      // shell.exec('echo ' + shell.escape(userInput)); // Manual escaping needed
+      // Not safe by default like other modern libraries
+      
+      expect(true).toBe(true); // Placeholder - manual escaping required
+    });
+
+    test('should provide escape utility', () => {
+      // ShellJS provides shell.escape() for manual input sanitization
+      // shell.escape(dangerousString) returns safely escaped version
+      
+      expect(true).toBe(true); // Placeholder - escape utility available
+    });
+  });
+
+  describe('Cross-platform Support', () => {
+    test('should work cross-platform', () => {
+      // ShellJS works on Windows, macOS, and Linux
+      // Implements shell commands in JavaScript for portability
+      
+      expect(true).toBe(true); // Placeholder - cross-platform
+    });
+
+    test('should provide JavaScript implementations of shell commands', () => {
+      // ShellJS reimplements common shell commands in pure JavaScript:
+      // shell.ls(), shell.cp(), shell.mv(), shell.rm(), etc.
+      
+      expect(true).toBe(true); // Placeholder - JavaScript implementations
+    });
+  });
+
+  describe('Performance', () => {
+    test('should have moderate performance', () => {
+      // ShellJS has moderate performance
+      // JavaScript implementations are slower than native commands
+      // But provides good cross-platform consistency
+      
+      expect(true).toBe(true); // Placeholder - moderate performance
+    });
+  });
+
+  describe('Memory Efficiency', () => {
+    test('should buffer in memory', () => {
+      // ShellJS buffers all command output in memory
+      // Synchronous operations return complete results
+      
+      expect(true).toBe(true); // Placeholder - buffers in memory
+    });
+  });
+
+  describe('Error Handling', () => {
+    test('should be configurable via set()', () => {
+      // ShellJS error handling is configurable:
+      // shell.set('+e'); // Continue on error (default)
+      // shell.set('-e'); // Exit on error
+      
+      expect(true).toBe(true); // Placeholder - configurable error handling
+    });
+
+    test('should return exit codes and output', () => {
+      // ShellJS commands return objects with:
+      // { code: 0, stdout: 'output', stderr: 'error' }
+      
+      expect(true).toBe(true); // Placeholder - exit codes and output
+    });
+  });
+
+  describe('Stdin Support', () => {
+    test('should support basic input through parameters', () => {
+      // ShellJS handles input through function parameters:
+      // shell.echo('input').to('file.txt');
+      // No interactive stdin support
+      
+      expect(true).toBe(true); // Placeholder - parameter input
+    });
+  });
+
+  describe('Built-in Commands', () => {
+    test('should have extensive built-in commands', () => {
+      // ShellJS provides JavaScript implementations of many shell commands:
+      // cat, cd, chmod, cp, echo, exec, find, grep, head, ln, ls, mkdir, mv, 
+      // pwd, rm, sed, tail, tempdir, test, touch, which
+      
+      expect(true).toBe(true); // Placeholder - extensive built-ins
+    });
+
+    test('should implement commands consistently across platforms', () => {
+      // ShellJS commands work identically on all platforms
+      // shell.ls() behaves the same on Windows and Unix
+      
+      expect(true).toBe(true); // Placeholder - consistent cross-platform
+    });
+  });
+
+  describe('Bundle Size', () => {
+    test('should have ~15KB bundle size', () => {
+      // ShellJS is moderate-sized due to JavaScript command implementations
+      // Includes implementations of many shell utilities
+      
+      expect(true).toBe(true); // Placeholder - ~15KB estimated
+    });
+  });
+
+  describe('TypeScript Support', () => {
+    test('should have TypeScript definitions', () => {
+      // ShellJS has TypeScript definitions available
+      // @types/shelljs provides type information
+      
+      expect(true).toBe(true); // Placeholder - TypeScript support
+    });
+  });
+
+  describe('Synchronous Execution', () => {
+    test('should be synchronous by default', () => {
+      // ShellJS is synchronous by default - rare in modern libraries
+      // const result = shell.exec('echo hello'); // Blocks until complete
+      // This is both an advantage (simplicity) and limitation (blocking)
+      
+      expect(true).toBe(true); // Placeholder - sync by default
+    });
+
+    test('should support async exec option', () => {
+      // ShellJS exec can be async with callback:
+      // shell.exec('command', { async: true }, (code, stdout, stderr) => {});
+      
+      expect(true).toBe(true); // Placeholder - async exec option
+    });
+  });
+
+  describe('Shell Configuration', () => {
+    test('should support shell configuration via set()', () => {
+      // ShellJS provides shell-like configuration:
+      // shell.set('-e'); // Exit on error
+      // shell.set('+e'); // Continue on error
+      // shell.set('-v'); // Verbose mode
+      
+      expect(true).toBe(true); // Placeholder - shell configuration
+    });
+
+    test('should support silent mode', () => {
+      // shell.exec('command', { silent: true }); // No stdout output
+      // Useful for capturing output without displaying it
+      
+      expect(true).toBe(true); // Placeholder - silent mode
+    });
+  });
+
+  describe('File System Operations', () => {
+    test('should excel at file system operations', () => {
+      // ShellJS is excellent for file operations:
+      // shell.cp('-r', 'src/*', 'dest/');
+      // shell.mkdir('-p', 'deep/nested/dirs');
+      // shell.find('src').filter(file => file.match(/\.js$/));
+      
+      expect(true).toBe(true); // Placeholder - excellent file operations
+    });
+
+    test('should support glob patterns', () => {
+      // ShellJS supports shell-style globbing:
+      // shell.ls('*.js');
+      // shell.rm('temp/*.tmp');
+      
+      expect(true).toBe(true); // Placeholder - glob pattern support
+    });
+  });
+
+  describe('Use Cases', () => {
+    test('should be ideal for build scripts', () => {
+      // ShellJS is popular for build scripts and automation:
+      // - Cross-platform file operations
+      // - Synchronous by default (simpler flow)
+      // - Rich built-in command set
+      
+      expect(true).toBe(true); // Placeholder - ideal for build scripts
+    });
+
+    test('should be good for simple automation', () => {
+      // ShellJS excels at:
+      // - File manipulation
+      // - Directory operations
+      // - Basic shell script automation
+      // Less suitable for complex process management
+      
+      expect(true).toBe(true); // Placeholder - good for simple automation
+    });
+  });
+
+  describe('Limitations', () => {
+    test('should lack modern async patterns', () => {
+      // ShellJS limitations:
+      // - Primarily synchronous (blocking)
+      // - No streaming capabilities
+      // - No template literals
+      // - Manual injection protection
+      
+      expect(true).toBe(true); // Placeholder - lacks modern async patterns
+    });
+
+    test('should have slower command execution', () => {
+      // JavaScript implementations are slower than native commands
+      // Trade-off: consistency vs performance
+      
+      expect(true).toBe(true); // Placeholder - slower execution
+    });
+  });
+});
\ No newline at end of file