Add more tests

Closes #3.

test/api.js

@@ -0,0 +1,52 @@
+"use strict";
+const { describe, it } = require("node:test");
+const assert = require("node:assert");
+const parseDataURL = require("..");
+/*
+  eslint
+  array-bracket-newline: ["error", "consistent"]
+  array-element-newline: "off"
+*/
+
+describe("Smoke tests via README examples", () => {
+  it("should parse no-type as expected", () => {
+    const textExample = parseDataURL("data:,Hello%2C%20World!");
+    assert.equal(textExample.mimeType.toString(), "text/plain;charset=US-ASCII");
+    assert.equal(textExample.body.constructor, Uint8Array);
+    assert.deepEqual(textExample.body, new Uint8Array([72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33]));
+  });
+
+  it("should parse text/html as expected", () => {
+    const htmlExample = parseDataURL("data:text/html,%3Ch1%3EHello%2C%20World!%3C%2Fh1%3E");
+    assert.equal(htmlExample.mimeType.toString(), "text/html");
+    assert.equal(htmlExample.body.constructor, Uint8Array);
+    assert.deepEqual(htmlExample.body, new Uint8Array([
+      60, 104, 49, 62, 72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33, 60, 47, 104, 49, 62
+    ]));
+  });
+
+  it("should parse img/png base64 as expected", () => {
+    const pngExample = parseDataURL("data:image/png;base64,iVBORw0KGgoAAA" +
+                                    "ANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4" +
+                                    "//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU" +
+                                    "5ErkJggg==");
+    assert.equal(pngExample.mimeType.toString(), "image/png");
+    assert.equal(pngExample.body.constructor, Uint8Array);
+    assert.deepEqual(pngExample.body, new Uint8Array([
+      137, 80, 78, 71, 13, 10, 26, 10, 0, 0, 0, 13,
+      73, 72, 68, 82, 0, 0, 0, 5, 0, 0, 0, 5,
+      8, 6, 0, 0, 0, 141, 111, 38, 229, 0, 0, 0,
+      28, 73, 68, 65, 84, 8, 215, 99, 248, 255, 255, 63,
+      195, 127, 6, 32, 5, 195, 32, 18, 132, 208, 49, 241,
+      130, 88, 205, 4, 0, 14, 245, 53, 203, 209, 142, 14,
+      31, 0, 0, 0, 0, 73, 69, 78, 68, 174, 66, 96,
+      130
+    ]));
+  });
+});
+
+describe("Additional coverage", () => {
+  it("should return null for non-data: URLs", () => {
+    assert.equal(parseDataURL("https://example.com/"), null);
+  });
+});