Add plugin, and ElemenAssertion class

packages/native/src/lib/ElementAssertion.ts

@@ -0,0 +1,9 @@
+import { Assertion } from "@assertive-ts/core";
+import { ReactTestInstance } from "react-test-renderer";
+
+export class ElementAssertion extends Assertion<ReactTestInstance> {
+    public constructor(actual: ReactTestInstance) {
+        super(actual);
+    }
+
+}

packages/native/src/main.ts

@@ -0,0 +1,32 @@
+import { Plugin } from "@assertive-ts/core";
+import { ReactTestInstance } from "react-test-renderer";
+
+import { ElementAssertion } from "./lib/ElementAssertion";
+
+declare module "@assertive-ts/core" {
+
+    export interface Expect {
+      // eslint-disable-next-line @typescript-eslint/prefer-function-type
+      (actual: ReactTestInstance): ElementAssertion;
+    }
+}
+
+const ElementPlugin: Plugin<ReactTestInstance, ElementAssertion> = {
+    Assertion: ElementAssertion,
+    insertAt: "top",
+    predicate: (actual): actual is ReactTestInstance =>
+        typeof actual === "object"
+        && actual !== null
+        && "instance" in actual
+        && typeof actual.instance === "object"
+        && "type" in actual
+        && typeof actual.type === "object"
+        && "props" in actual
+        && typeof actual.props === "object"
+        && "parent" in actual
+        && typeof actual.parent === "object"
+        && "children" in actual
+        && typeof actual.children === "object",
+};
+
+export const NativePlugin = [ElementPlugin];