test: add unit tests for index exports

Author: jamaljsr

lib/index.test.ts

@@ -0,0 +1,69 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+// Mock the wasm_exec module
+vi.mock('../../lib/wasm_exec', () => ({}));
+
+// Mock @lightninglabs/lnc-core to avoid actual imports
+vi.mock('@lightninglabs/lnc-core');
+
+describe('Index Module', () => {
+    let originalInstantiateStreaming: any;
+
+    beforeEach(() => {
+        // Store original values
+        originalInstantiateStreaming =
+            globalThis.WebAssembly?.instantiateStreaming;
+
+        // Mock WebAssembly for testing
+        globalThis.WebAssembly = {
+            instantiateStreaming: vi.fn(),
+            instantiate: vi.fn(),
+            compile: vi.fn()
+        } as any;
+    });
+
+    afterEach(() => {
+        // Restore original values
+        if (originalInstantiateStreaming) {
+            globalThis.WebAssembly.instantiateStreaming =
+                originalInstantiateStreaming;
+        }
+        vi.restoreAllMocks();
+    });
+
+    describe('WebAssembly Polyfill', () => {
+        it('should polyfill WebAssembly.instantiateStreaming when not available', async () => {
+            // Remove instantiateStreaming to test polyfill
+            delete (globalThis.WebAssembly as any).instantiateStreaming;
+
+            // Import the index module to trigger the polyfill
+            await import('./index');
+
+            // Now WebAssembly.instantiateStreaming should exist
+            expect(typeof globalThis.WebAssembly?.instantiateStreaming).toBe(
+                'function'
+            );
+        });
+
+        it('should use existing WebAssembly.instantiateStreaming when available', async () => {
+            // Set up existing WebAssembly.instantiateStreaming
+            const existingInstantiateStreaming = vi.fn().mockResolvedValue({
+                module: {},
+                instance: {}
+            });
+
+            globalThis.WebAssembly = {
+                ...globalThis.WebAssembly,
+                instantiateStreaming: existingInstantiateStreaming
+            };
+
+            // Import the index module
+            await import('./index');
+
+            // The existing function should still be there
+            expect(globalThis.WebAssembly.instantiateStreaming).toBe(
+                existingInstantiateStreaming
+            );
+        });
+    });
+});