init geek calc

tests/unit/calculator.test.js

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+// Contract test for Core Calculator API
+// This test should fail initially since the calculator module doesn't exist yet
+
+// Define expected interface for calculator module
+const expectedCalculatorInterface = [
+  'evaluate',
+  'add', 
+  'subtract',
+  'multiply',
+  'divide',
+  'percentage',
+  'toggleSign',
+  'clear',
+  'getCurrentDisplay'
+];
+
+// Test if calculator module exists and has expected interface
+function testCalculatorInterface() {
+    try {
+        // This will fail since calculator.js doesn't exist yet
+        const calc = new Calculator();
+        
+        // Check if all expected methods exist
+        for (const method of expectedCalculatorInterface) {
+            if (typeof calc[method] !== 'function') {
+                throw new Error(`Method ${method} does not exist on Calculator`);
+            }
+        }
+        
+        // Test basic functionality
+        // Add should return sum of two numbers
+        if (calc.add(2, 3) !== 5) {
+            throw new Error('Calculator add method does not return correct result');
+        }
+        
+        // Subtract should return difference
+        if (calc.subtract(5, 3) !== 2) {
+            throw new Error('Calculator subtract method does not return correct result');
+        }
+        
+        // Multiply should return product
+        if (calc.multiply(4, 5) !== 20) {
+            throw new Error('Calculator multiply method does not return correct result');
+        }
+        
+        // Divide should return quotient
+        if (calc.divide(10, 2) !== 5) {
+            throw new Error('Calculator divide method does not return correct result');
+        }
+        
+        // Division by zero should return Infinity
+        if (!isFinite(calc.divide(10, 0))) {
+            // This is expected, division by zero returns Infinity
+        } else {
+            throw new Error('Calculator divide by zero does not return Infinity');
+        }
+        
+        // Percentage should convert percentage to decimal
+        if (calc.percentage(50) !== 0.5) {
+            throw new Error('Calculator percentage method does not return correct result');
+        }
+        
+        // ToggleSign should change sign
+        if (calc.toggleSign(5) !== -5) {
+            throw new Error('Calculator toggleSign method does not return correct result');
+        }
+        
+        if (calc.toggleSign(-5) !== 5) {
+            throw new Error('Calculator toggleSign method does not return correct result for negative number');
+        }
+        
+        // Clear should reset to initial state
+        calc.clear();
+        if (calc.getCurrentDisplay() !== '0') {
+            throw new Error('Calculator clear method does not reset to initial state');
+        }
+        
+        // Evaluate should handle simple expressions
+        if (calc.evaluate('2 + 3') !== 5) {
+            throw new Error('Calculator evaluate method does not return correct result');
+        }
+        
+        return true; // All tests passed
+    } catch (error) {
+        return { error: error.message };
+    }
+}
+
+// Add test to global test collection
+if (typeof addTest !== 'undefined') {
+    addTest('Calculator Interface Contract', testCalculatorInterface);
+} else {
+    console.log('Test harness not loaded. Run with test runner.');
+}