chore: increase coverage on a couple of functions

Signed-off-by: Case Wylie <[email protected]>

src/cli/init/utils.test.ts

@@ -1,9 +1,16 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2023-Present The Pepr Authors
 
-import { expect, it } from "@jest/globals";
+import { expect, it, jest, describe, afterEach } from "@jest/globals";
+import { promises as fs } from "fs";
+import { sanitizeName, createDir, write } from "./utils";
 
-import { sanitizeName } from "./utils";
+jest.mock("fs", () => ({
+  promises: {
+    mkdir: jest.fn(),
+    writeFile: jest.fn(),
+  },
+}));
 
 it.each([
   //Test sanitizeName() with ["$BAD_INPUT", "$SANITIZED_INPUT"]
@@ -17,3 +24,59 @@ it.each([
 it("sanitizeName() should throw TypeError when given a non-string", () => {
   expect(() => sanitizeName({ input: 0 } as unknown as string)).toThrow(TypeError);
 });
+
+describe("createDir", () => {
+  const mockedMkdir = fs.mkdir as jest.Mock;
+
+  afterEach(() => {
+    jest.clearAllMocks(); // Clear mocks between tests
+  });
+
+  it("should create the pepr-test-module dir", async () => {
+    await createDir("pepr-test-module");
+    expect(mockedMkdir).toHaveBeenCalledWith("pepr-test-module");
+  });
+
+  it("should throw an error if the directory already exists", async () => {
+    const error = new Error("Directory already exists") as NodeJS.ErrnoException;
+    error.code = "EEXIST";
+    mockedMkdir.mockRejectedValueOnce(error as unknown as never);
+
+    await expect(createDir("pepr-test-module")).rejects.toThrow(
+      "Directory pepr-test-module already exists",
+    );
+    expect(mockedMkdir).toHaveBeenCalledTimes(1);
+    expect(mockedMkdir).toHaveBeenCalledWith("pepr-test-module");
+  });
+
+  it("should throw the error if there is another error other than already exists", async () => {
+    const error = new Error("Directory already exists") as NodeJS.ErrnoException;
+    error.code = "ENOENT";
+    mockedMkdir.mockRejectedValueOnce(error as unknown as never);
+
+    await expect(createDir("pepr-test-module")).rejects.toThrow(error);
+    expect(mockedMkdir).toHaveBeenCalledTimes(1);
+    expect(mockedMkdir).toHaveBeenCalledWith("pepr-test-module");
+  });
+});
+
+describe("write", () => {
+  const mockedWriteFile = fs.writeFile as jest.Mock;
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it("should write data to a file", async () => {
+    await write("package.json", "pepr-test-module");
+    expect(mockedWriteFile).toHaveBeenCalledWith("package.json", "pepr-test-module");
+  });
+
+  it("should stringify data if it is not a string", async () => {
+    await write("package.json", { name: "pepr-test-module" });
+    expect(mockedWriteFile).toHaveBeenCalledWith(
+      "package.json",
+      JSON.stringify({ name: "pepr-test-module" }, null, 2),
+    );
+  });
+});