fix: query params with same keys are added to the collection

BREAKING CHANGE:

Query params on a router link with the same key are no longer overwriting the last value.
Instead they are added to an array.

Author: timdeschryver

Diff for: projects/testing-library/src/lib/testing-library.ts

@@ -130,8 +130,14 @@ export async function render<SutType, WrapperType = SutType>(
     const queryParams = params
       ? params.split('&').reduce((qp, q) => {
           const [key, value] = q.split('=');
-          // TODO(Breaking): group same keys qp[key] ? [...qp[key], value] : value
-          qp[key] = value;
+          const currentValue = qp[key];
+          if (typeof currentValue === 'undefined') {
+            qp[key] = value;
+          } else if (Array.isArray(currentValue)) {
+            qp[key] = [...currentValue, value];
+          } else {
+            qp[key] = [currentValue, value];
+          }
           return qp;
         }, {})
       : undefined;