Adding cypress + example test (#476)

frontend/src/components/TextInput.cy.tsx

@@ -0,0 +1,26 @@
+import TextInput from "../components/TextInput";
+
+describe("TextInput", () => {
+  const label = "label";
+  const placeholder = "some placeholder";
+
+  beforeEach(() => {
+    cy.mount(
+      <TextInput
+        label={label}
+        placeholder={placeholder}
+        onChange={() => {
+          return;
+        }}
+      />
+    );
+  });
+
+  it("contains correct label", () => {
+    cy.get("label").should("contain", label);
+  });
+
+  it("contains correct placeholder", () => {
+    cy.get("input").should("have.attr", "placeholder", placeholder);
+  });
+});