Add CLI tests

test/cli.js

@@ -0,0 +1,61 @@
+import { exec as execCallback } from "node:child_process";
+import { join as joinPaths, dirname as pathDirname } from "node:path";
+import { fileURLToPath } from "node:url";
+import { promisify } from "node:util";
+import tap from "tap";
+
+const exec = promisify(execCallback);
+
+/**
+ * @file
+ * This test checks that basic CLI functionality works.
+ */
+
+/**
+ * TODO: replace with `import.meta.dirname` when it becomes stable:
+ * https://nodejs.org/api/esm.html#importmeta
+ */
+const dirname = pathDirname(fileURLToPath(import.meta.url));
+
+const cwd = joinPaths(dirname, "..");
+const sizeOfFixtureFolder = "0.01 MB";
+
+for (const folderArg of ["--folder=", "-f=", ""]) {
+	const args = `${folderArg}test/fixture`;
+
+	tap.test(`get folder size with args: ${args}`, async () => {
+		const result = await exec(`bin/get-folder-size.js ${args}`, {
+			cwd,
+		});
+
+		tap.ok(
+			result.stdout.startsWith(sizeOfFixtureFolder),
+			"should return the size of the folder",
+		);
+	});
+
+	for (const ignoreArg of ["--ignore=", "-i="]) {
+		for (const flipArgs of [false, true]) {
+			const arg1 = `${folderArg}test/fixture`;
+			const arg2 = `${ignoreArg}.*txt`;
+			const args = flipArgs ? `${arg2} ${arg1}` : `${arg1} ${arg2}`;
+
+			tap.test(`get folder size with args: ${args}`, async () => {
+				const result = await exec(`bin/get-folder-size.js ${args}`, {
+					cwd,
+				});
+
+				tap.ok(
+					result.stdout.startsWith("0.00 MB"),
+					"should return zero as size",
+				);
+			});
+		}
+	}
+}
+
+tap.test("get folder size with missing args", async () => {
+	tap.rejects(async () => {
+		await exec("bin/get-folder-size.js", { cwd });
+	}, "should reject since no folder path is provided");
+});