chore: add cli unit test (#15)

__tests__/cli.test.ts

@@ -0,0 +1,65 @@
+import * as cp from "child_process";
+import * as path from "path";
+
+import { readFileSync, writeFileSync } from "fs";
+
+test("CLI: update readme default", async () => {
+  await testReadme(
+    "__tests__/fixtures/all_fields_action.yml",
+    "__tests__/fixtures/all_fields_readme.input",
+    "__tests__/fixtures/all_fields_readme.output"
+  );
+});
+
+test("CLI: update readme CRLF", async () => {
+  await testReadme(
+    "__tests__/fixtures/all_fields_action.yml.crlf",
+    "__tests__/fixtures/all_fields_readme.input.crlf",
+    "__tests__/fixtures/all_fields_readme.output.crlf",
+    "--lb CRLF"
+  );
+});
+
+interface CliRespone {
+  code: number;
+  error: cp.ExecException | null;
+  stdout: string;
+  stderr: string;
+}
+
+function cli(args: string): Promise<CliRespone> {
+  return new Promise((resolve) => {
+    cp.exec(
+      `ts-node ${path.resolve("src/cli.ts")} ${args}`,
+      (error, stdout, stderr) => {
+        resolve({
+          code: error && error.code ? error.code : 0,
+          error,
+          stdout,
+          stderr,
+        });
+      }
+    );
+  });
+}
+
+async function testReadme(
+  actionFile: string,
+  originalReadme: string,
+  fixtureReadme: string,
+  extraArgs = "",
+  exitCode = 0
+) {
+  const expected = <string>readFileSync(fixtureReadme, "utf-8");
+  const original = <string>readFileSync(originalReadme, "utf-8");
+
+  const result = await cli(
+    `-u ${originalReadme} -a ${actionFile} ${extraArgs}`
+  );
+  expect(result.code).toBe(exitCode);
+
+  const updated = <string>readFileSync(originalReadme, "utf-8");
+
+  writeFileSync(originalReadme, original);
+  expect(updated).toEqual(expected);
+}