test: add canvas replacement test

src/canvas replacement.test.js

@@ -0,0 +1,36 @@
+import {
+	end, press, snapshot, start,
+} from './test/bitsy';
+
+test('canvas replacement', async () => {
+	await start({
+		hacks: [
+			[
+				'canvas replacement',
+				{
+					glazyOptions: {
+						background: 'black',
+						scaleMode: 'FIT',
+						allowDownscaling: true,
+						disableFeedbackTexture: true,
+						fragment: `
+// tint fragment shader
+precision mediump float;
+uniform sampler2D tex0;
+uniform sampler2D tex1;
+uniform float time;
+uniform vec2 resolution;
+
+void main(){
+	gl_FragColor = vec4(texture2D(tex0, gl_FragCoord.xy / resolution.xy).rg, 0.0, 1.0);
+}`,
+					},
+				},
+			],
+		],
+	});
+	await press('Enter'); // complete title page
+	await press('Enter'); // end title page
+	await snapshot();
+	await end();
+});