test: add unit tests for makeApi and runExtensions

Adds tests for src/extensions.ts to improve test coverage and reliability.
Checks that makeApi delegates to the engine correctly, and that
runExtensions properly evaluates Javascript and handles errors appropriately.

Co-authored-by: Horizontal42 <75383519+Horizontal42@users.noreply.github.com>

src/extensions.test.ts

@@ -0,0 +1,108 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { makeApi, runExtensions } from "./extensions";
+import { SumEngine } from "./engine";
+
+describe("extensions", () => {
+  let mockEngine: any;
+
+  beforeEach(() => {
+    mockEngine = {
+      setVariable: vi.fn(),
+      addUnit: vi.fn(),
+      addFunction: vi.fn(),
+    };
+  });
+
+  describe("makeApi", () => {
+    it("delegates setVariable to engine", () => {
+      const api = makeApi(mockEngine as SumEngine);
+      api.setVariable("myVar", 42);
+      expect(mockEngine.setVariable).toHaveBeenCalledWith("myVar", 42);
+    });
+
+    it("delegates addUnit to engine", () => {
+      const api = makeApi(mockEngine as SumEngine);
+      const spec = { id: "testUnit", phrases: "tests", baseUnitId: "USD", ratio: 1 };
+      api.addUnit(spec);
+      expect(mockEngine.addUnit).toHaveBeenCalledWith(spec);
+    });
+
+    it("delegates addFunction to engine", () => {
+      const api = makeApi(mockEngine as SumEngine);
+      const spec = { id: "testFunc", phrases: "test" };
+      const fn = () => 42;
+      api.addFunction(spec, fn);
+      expect(mockEngine.addFunction).toHaveBeenCalledWith(spec, fn);
+    });
+  });
+
+  describe("runExtensions", () => {
+    let consoleErrorSpy: any;
+
+    beforeEach(() => {
+      consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    });
+
+    afterEach(() => {
+      consoleErrorSpy.mockRestore();
+    });
+
+    it("runs scripts successfully using numi api", () => {
+      const scripts = [
+        {
+          name: "script1",
+          code: "numi.setVariable('var1', 10);",
+        },
+        {
+          name: "script2",
+          code: "numi.addUnit({ id: 'unit1', phrases: 'u', baseUnitId: 'USD', ratio: 1 });",
+        },
+      ];
+
+      runExtensions(mockEngine as SumEngine, scripts);
+
+      expect(mockEngine.setVariable).toHaveBeenCalledWith("var1", 10);
+      expect(mockEngine.addUnit).toHaveBeenCalledWith({ id: "unit1", phrases: "u", baseUnitId: "USD", ratio: 1 });
+      expect(consoleErrorSpy).not.toHaveBeenCalled();
+    });
+
+    it("swallows errors and logs to console.error", () => {
+      const scripts = [
+        {
+          name: "script1",
+          code: "throw new Error('test error');",
+        },
+      ];
+
+      runExtensions(mockEngine as SumEngine, scripts);
+
+      expect(consoleErrorSpy).toHaveBeenCalledWith(
+        "extension script1 failed:",
+        expect.any(Error)
+      );
+    });
+
+    it("continues running other scripts if one fails", () => {
+      const scripts = [
+        {
+          name: "script1",
+          code: "numi.setVariable('var1', 10);",
+        },
+        {
+          name: "script2",
+          code: "throw new Error('boom');",
+        },
+        {
+          name: "script3",
+          code: "numi.setVariable('var3', 30);",
+        },
+      ];
+
+      runExtensions(mockEngine as SumEngine, scripts);
+
+      expect(mockEngine.setVariable).toHaveBeenCalledWith("var1", 10);
+      expect(mockEngine.setVariable).toHaveBeenCalledWith("var3", 30);
+      expect(consoleErrorSpy).toHaveBeenCalledTimes(1);
+    });
+  });
+});