imp: qweb engine can be initialized with templates

src/qweb.ts

@@ -182,7 +182,7 @@ export class QWeb {
   templates: { [name: string]: CompiledTemplate<VNode> } = {};
   directives: Directive[] = [];
 
-  constructor() {
+  constructor(data?: string) {
     [
       forEachDirective,
       escDirective,
@@ -196,6 +196,10 @@ export class QWeb {
       refDirective,
       widgetDirective
     ].forEach(d => this.addDirective(d));
+
+    if (data) {
+      this.loadTemplates(data);
+    }
   }
 
   utils = {

tests/__snapshots__/qweb.test.ts.snap

@@ -464,6 +464,17 @@ exports[`foreach iterate, position 1`] = `
 }"
 `;
 
+exports[`loading templates can initialize qweb with a string 1`] = `
+"function anonymous(context,extra
+) {
+    let h = this.utils.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    c1.push({text: \`jupiler\`});
+    return vn1;
+}"
+`;
+
 exports[`loading templates can load a few templates from a xml string 1`] = `
 "function anonymous(context,extra
 ) {

tests/qweb.test.ts

@@ -878,6 +878,16 @@ describe("t-ref", () => {
 });
 
 describe("loading templates", () => {
+  test("can initialize qweb with a string", () => {
+    const data = `
+      <?xml version="1.0" encoding="UTF-8"?>
+      <templates id="template" xml:space="preserve">
+        <div t-name="hey">jupiler</div>
+      </templates>`;
+    const qweb = new QWeb(data);
+    expect(renderToString(qweb, "hey")).toBe("<div>jupiler</div>");
+  });
+
   test("can load a few templates from a xml string", () => {
     const data = `
       <?xml version="1.0" encoding="UTF-8"?>