test: add unit tests for internal utils (#77)

test/utils.test.ts

@@ -0,0 +1,78 @@
+import { describe, it, expect } from "vitest";
+import {
+  toArray,
+  formatLineColumns,
+  resolveValue,
+  CLIError,
+} from "../src/_utils";
+import type { Resolvable } from "../src/types";
+
+describe("toArray()", () => {
+  it.concurrent("should return empty array if input is undefined", () => {
+    expect(toArray(undefined)).toEqual([]);
+  });
+
+  it.concurrent("should return the same array if input is an array", () => {
+    expect(toArray([1, 2, 3])).toEqual([1, 2, 3]);
+  });
+
+  it.concurrent(
+    "should return an array containing the input if it is not an array",
+    () => {
+      expect(toArray(1)).toEqual([1]);
+      expect(toArray("hello")).toEqual(["hello"]);
+    },
+  );
+});
+describe("formatLineColumns()", () => {
+  it.concurrent("should format lines correctly", () => {
+    const lines = [
+      ["Name", "Age"],
+      ["Alice", "30"],
+      ["Bob", "40"],
+    ];
+    const result = formatLineColumns(lines);
+    expect(result).toBe(" Name  Age\nAlice  30 \n  Bob  40 ");
+  });
+
+  it.concurrent("should prepend a line prefix if provided", () => {
+    const lines = [
+      ["Name", "Age"],
+      ["Alice", "30"],
+      ["Bob", "40"],
+    ];
+    const result = formatLineColumns(lines, "--");
+    expect(result).toBe("-- Name  --Age\n--Alice  --30 \n--  Bob  --40 ");
+  });
+});
+
+describe("resolveValue()", () => {
+  it("should resolve a non-function value correctly", () => {
+    const value: Resolvable<number> = 42;
+    const result = resolveValue(value);
+    expect(result).toBe(42);
+  });
+
+  it("should resolve a function value correctly", () => {
+    // eslint-disable-next-line unicorn/consistent-function-scoping
+    const value: Resolvable<number> = () => 42;
+    const result = resolveValue(value);
+    expect(result).toBe(42);
+  });
+});
+
+describe("CLIError", () => {
+  it("should correctly create an instance with a message", () => {
+    const error = new CLIError("An error occurred");
+    expect(error.message).toBe("An error occurred");
+    expect(error.name).toBe("CLIError");
+    expect(error.code).toBeUndefined();
+  });
+
+  it("should correctly create an instance with a message and code", () => {
+    const error = new CLIError("An error occurred", "ERROR_CODE");
+    expect(error.message).toBe("An error occurred");
+    expect(error.name).toBe("CLIError");
+    expect(error.code).toBe("ERROR_CODE");
+  });
+});