PageSourceHandler integration tests

Add integration tests for /page/{title} endpoint
Bug: T229663

Change-Id: If8e140f70c518a8fa5e5eaef46f87a383c813e40

tests/api-testing/REST/PageSource.js

@@ -0,0 +1,47 @@
+const { action, assert, REST, utils } = require( 'api-testing' );
+
+describe( 'Page Source', () => {
+	const page = utils.title( 'PageSource ' );
+	const client = new REST( 'rest.php/coredev/v0' );
+	const anon = action.getAnon();
+
+	before( async () => {
+		await anon.edit( page, { text: "''Edit 1'' and '''Edit 2'''" } );
+	} );
+
+	describe( 'GET /page/{title}', () => {
+		it( 'Should successfully return page source and metadata for Wikitext page', async () => {
+			const { status, body } = await client.get( `/page/${page}` );
+			assert.deepEqual( status, 200 );
+			assert.containsAllKeys( body, [ 'latest', 'id', 'key', 'license', 'title', 'content_model', 'source' ] );
+			assert.nestedPropertyVal( body, 'content_model', 'text' );
+			assert.nestedPropertyVal( body, 'title', page );
+			assert.nestedPropertyVal( body, 'key', utils.dbkey( page ) );
+			assert.nestedPropertyVal( body, 'source', "''Edit 1'' and '''Edit 2'''" );
+		} );
+		it( 'Should return 404 error for non-existent page', async () => {
+			const dummyPageTitle = utils.title( 'DummyPage_' );
+			const { status } = await client.get( `/page/${dummyPageTitle}` );
+			assert.deepEqual( status, 404 );
+		} );
+		it( 'Should have appropriate response headers', async () => {
+			const preEditResponse = await client.get( `/page/${page}` );
+			const preEditDate = new Date( preEditResponse.body.latest.timestamp );
+			const preEditEtag = preEditResponse.headers.etag;
+
+			await anon.edit( page, { text: "'''Edit 3'''" } );
+			const postEditResponse = await client.get( `/page/${page}` );
+			const postEditDate = new Date( postEditResponse.body.latest.timestamp );
+			const postEditHeaders = postEditResponse.headers;
+			const postEditEtag = postEditResponse.headers.etag;
+
+			assert.containsAllKeys( postEditHeaders, [ 'etag' ] );
+			assert.deepEqual( postEditHeaders[ 'last-modified' ], postEditDate.toGMTString() );
+			assert.match( postEditHeaders[ 'cache-control' ], /^maxage=\d/ );
+			assert.strictEqual( isNaN( preEditDate.getTime() ), false );
+			assert.strictEqual( isNaN( postEditDate.getTime() ), false );
+			assert.notEqual( preEditDate, postEditDate );
+			assert.notEqual( preEditEtag, postEditEtag );
+		} );
+	} );
+} );