[IMP] *: re-add a bunch of tests

tests/qweb/__snapshots__/error_handling.test.ts.snap

@@ -0,0 +1,15 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`error handling cannot add twice the same template 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    return block1();
+  }
+}"
+`;