[FEATURE] Add test runner middleware

Static resources are copied over from OpenUI5.

.eslintignore

@@ -1,5 +1,8 @@
 # /node_modules/* and /bower_components/* ignored by default
 
+# Ignore test runner static resources
+lib/middleware/testRunner/
+
 # Exclude coverage folder
 coverage/
 

lib/middleware/MiddlewareManager.js

@@ -121,6 +121,7 @@ class MiddlewareManager {
 			mountPath: "/discovery"
 		});
 		await this.addMiddleware("serveResources");
+		await this.addMiddleware("testRunner");
 		await this.addMiddleware("serveThemes");
 		await this.addMiddleware("versionInfo", {
 			mountPath: "/resources/sap-ui-version.json",

lib/middleware/middlewareRepository.js

@@ -8,6 +8,7 @@ const middlewares = {
 	versionInfo: "./versionInfo",
 	connectUi5Proxy: "./connectUi5Proxy",
 	serveThemes: "./serveThemes",
+	testRunner: "./testRunner",
 	nonReadRequests: "./nonReadRequests"
 };
 

lib/middleware/testRunner.js

@@ -0,0 +1,59 @@
+const {promisify} = require("util");
+const fs = require("graceful-fs");
+const readFile = promisify(fs.readFile);
+const path = require("path");
+const mime = require("mime-types");
+const log = require("@ui5/logger").getLogger("server:middleware:testRunner");
+
+const testRunnerResourceRegEx = /\/test-resources\/sap\/ui\/qunit\/(testrunner\.(html|css)|TestRunner.js)$/;
+const resourceCache = {};
+
+function serveResource(res, resourcePath, resourceContent) {
+	const type = mime.lookup(resourcePath) || "application/octet-stream";
+	const charset = mime.charset(type);
+	const contentType = type + (charset ? "; charset=" + charset : "");
+
+	// resources served by this middleware do not change often
+	res.setHeader("Cache-Control", "public, max-age=1800");
+
+	res.setHeader("Content-Type", contentType);
+	res.end(resourceContent);
+}
+
+/**
+ * Creates and returns the middleware to serve a resource index.
+ *
+ * @module @ui5/server/middleware/testRunner
+ * @param {object} parameters Parameters
+ * @param {object} parameters.resources Contains the resource reader or collection to access project related files
+ * @returns {Function} Returns a server middleware closure.
+ */
+function createMiddleware({resources}) {
+	return async function(req, res, next) {
+		try {
+			const pathname = req.path; // TODO: Other middlewares use the parseurl module here but I don't get why
+			const parts = testRunnerResourceRegEx.exec(pathname);
+			const resourceName = parts && parts[1];
+
+			if (resourceName) { // either "testrunner.html", "testrunner.css" or "TestRunner.js" (case sensitive!)
+				log.verbose(`Serving ${pathname}`);
+				let pResource;
+				if (!resourceCache[pathname]) {
+					pResource = readFile(path.join(__dirname, "testRunner", resourceName), {encoding: "utf8"});
+					resourceCache[pathname] = pResource;
+				} else {
+					pResource = resourceCache[pathname];
+				}
+
+				const resourceContent = await pResource;
+				serveResource(res, pathname, resourceContent);
+			} else {
+				next();
+			}
+		} catch (err) {
+			next(err);
+		}
+	};
+}
+
+module.exports = createMiddleware;