Add testcases - utils.getRootFiberNodeFromDOM

test/utils.getRootFiberNodeFromDOM.spec.tsx

@@ -0,0 +1,80 @@
+// import * as React from "react";
+
+// Import stuff from src
+import { getRootFiberNodeFromDOM } from "../src/utils";
+
+// Import test helpers and sample components
+import { mountAndGetRootNode } from "./utils/mountInEnzyme";
+import { createClassComponent } from "./utils/createComponent";
+
+describe("traverse", () => {
+  let container: HTMLDivElement;
+
+  beforeEach(() => {
+    container = document.body.appendChild(document.createElement("div"));
+  });
+
+  afterEach(() => {
+    try {
+      document.body.removeChild(container);
+    } catch (error) {
+      if (!(error instanceof DOMException)) {
+        throw error;
+      }
+    }
+  });
+
+  describe("getRootFiberNodeFromDOM", () => {
+    it("should work for direct element", () => {
+      const C1 = createClassComponent("C1");
+      const containerInner = container.appendChild(
+        document.createElement("span")
+      );
+      mountAndGetRootNode(C1, containerInner);
+
+      const resultPositive = getRootFiberNodeFromDOM(containerInner);
+
+      expect(resultPositive).not.toBeFalsy();
+      expect(resultPositive).not.toBe(null);
+      expect((resultPositive as any).child.child.type).toBe(C1);
+    });
+
+    it("should work for parent element", () => {
+      const C1 = createClassComponent("C1");
+      const containerInner = container.appendChild(
+        document.createElement("span")
+      );
+      mountAndGetRootNode(C1, containerInner);
+
+      const resultPositive = getRootFiberNodeFromDOM(container);
+
+      expect(resultPositive).not.toBeFalsy();
+      expect(resultPositive).not.toBe(null);
+      expect((resultPositive as any).child.child.type).toBe(C1);
+    });
+
+    it("should not work for child element", () => {
+      const C1 = createClassComponent("C1");
+      const containerInner = container.appendChild(
+        document.createElement("span")
+      );
+      mountAndGetRootNode(C1, container);
+
+      const resultNegative = getRootFiberNodeFromDOM(containerInner);
+
+      expect(resultNegative).toBeFalsy();
+      expect(resultNegative).toBe(null);
+    });
+
+    it("should work for body", () => {
+      const C1 = createClassComponent("C1");
+      mountAndGetRootNode(C1, document.body);
+
+      const resultPositive = getRootFiberNodeFromDOM(document.body);
+
+      expect(resultPositive).not.toBeFalsy();
+      expect(resultPositive).not.toBe(null);
+      expect((resultPositive as any).child.child.type).toBe(C1);
+    });
+  });
+});