diff --git a/reconcile-js/__mocks__/wasm.js b/reconcile-js/__mocks__/wasm.js
new file mode 100644
index 0000000..e67f920
--- /dev/null
+++ b/reconcile-js/__mocks__/wasm.js
@@ -0,0 +1,9 @@
+const fs = require('fs');
+const path = require('path');
+
+// Read the actual WASM file and convert to base64 for testing
+const wasmPath = path.join(__dirname, '../../pkg/reconcile_bg.wasm');
+const wasmBuffer = fs.readFileSync(wasmPath);
+const wasmBase64 = wasmBuffer.toString('base64');
+
+module.exports = wasmBase64;
diff --git a/reconcile-js/jest.config.js b/reconcile-js/jest.config.js
index 8c1027e..d8542ff 100644
--- a/reconcile-js/jest.config.js
+++ b/reconcile-js/jest.config.js
@@ -1,3 +1,6 @@
 module.exports = {
-	preset: "ts-jest/presets/js-with-babel-esm"
+  preset: 'ts-jest/presets/js-with-babel-esm',
+  moduleNameMapper: {
+    '^reconcile/reconcile_bg\\.wasm$': `<rootDir>/__mocks__/wasm.js`,
+  },
 };