Add Jest unit testing without package.json

- Set up Jest testing using npx with custom testMatch configuration
- Add environment detection to prevent browser code from running in Node.js tests
- Export functions for testing while maintaining browser compatibility
- Create initial tests for getQueryParam function with 3 test cases
- Add make test command for easy test execution
- Use tests/ directory instead of __tests__ for cleaner project structure

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: thavelick

Makefile

@@ -23,6 +23,10 @@ check: # Check formatting and linting with Biome
 	@echo "Checking formatting and linting.."
 	npx @biomejs/biome check .
 
+test: # Run unit tests with Jest
+	@echo "Running tests.."
+	npx jest -c '{"testMatch":["**/tests/**/*.spec.js"]}'
+
 # -----------------------------------------------------------
 # CAUTION: If you have a file with the same name as make
 # command, you need to add it to .PHONY below, otherwise it

public_html/script.js

@@ -160,4 +160,15 @@ function initialize() {
   }
 }
 
-initialize();
+// Only initialize in browser environment
+if (typeof window !== "undefined") {
+  initialize();
+}
+
+// Export functions for testing (Node.js environment)
+if (typeof module !== "undefined" && module.exports) {
+  module.exports = {
+    getQueryParam,
+    processBang,
+  };
+}

tests/script.spec.js

@@ -0,0 +1,34 @@
+const { getQueryParam } = require("../public_html/script.js");
+
+describe("getQueryParam", () => {
+  // Mock window.location.search for testing
+  const originalLocation = global.window?.location;
+  
+  beforeEach(() => {
+    delete global.window;
+    global.window = {
+      location: {
+        search: ""
+      }
+    };
+  });
+  
+  afterEach(() => {
+    global.window = originalLocation;
+  });
+
+  test("returns null for missing parameter", () => {
+    global.window.location.search = "?foo=bar";
+    expect(getQueryParam("missing")).toBeNull();
+  });
+
+  test("returns value for existing parameter", () => {
+    global.window.location.search = "?q=test+query";
+    expect(getQueryParam("q")).toBe("test query");
+  });
+
+  test("handles empty search string", () => {
+    global.window.location.search = "";
+    expect(getQueryParam("q")).toBeNull();
+  });
+});