From 0b799d64b7ec5a7d774f239b42b854810b03fdc9 Mon Sep 17 00:00:00 2001
From: Eric Liu <ericyl.us@gmail.com>
Date: Thu, 20 Mar 2025 16:28:46 -0700
Subject: [PATCH] test(dropdown): add unit tests

---
 tests/Dropdown.test.svelte              | 115 ----------
 tests/Dropdown/Dropdown.test.svelte     |  53 +++++
 tests/Dropdown/Dropdown.test.ts         | 266 ++++++++++++++++++++++++
 tests/Dropdown/DropdownSlot.test.svelte |  25 +++
 4 files changed, 344 insertions(+), 115 deletions(-)
 delete mode 100644 tests/Dropdown.test.svelte
 create mode 100644 tests/Dropdown/Dropdown.test.svelte
 create mode 100644 tests/Dropdown/Dropdown.test.ts
 create mode 100644 tests/Dropdown/DropdownSlot.test.svelte

diff --git a/tests/Dropdown.test.svelte b/tests/Dropdown.test.svelte
deleted file mode 100644
index 3ba410d6..00000000
--- a/tests/Dropdown.test.svelte
+++ /dev/null
@@ -1,115 +0,0 @@
-<script lang="ts">
-  import { Dropdown, DropdownSkeleton } from "carbon-components-svelte";
-  import type { DropdownProps } from "carbon-components-svelte/Dropdown/Dropdown.svelte";
-
-  let items = [
-    { id: 0, text: "Slack" },
-    { id: "1", text: "Email" },
-    { id: "2", text: "Fax" },
-  ] satisfies NonNullable<DropdownProps["items"]>;
-
-  let itemsWithoutConst = [...items];
-
-  type FieldId = (typeof items)[number]["id"]; // 'foo' | 'bar' | 'baz'
-
-  export const fieldId: FieldId = "bar";
-
-  $: items[0] = { id: "0", text: "Slack" };
-  $: {
-    items[0] = { id: "0", text: "Slack" };
-  }
-  $: {
-    items = [...items, { id: "3", text: "Email" }];
-    items = items.map((item, index) => {
-      if (index === 0) {
-        return { id: "0", text: "Slack" };
-      }
-      return item;
-    });
-  }
-</script>
-
-<Dropdown
-  direction="top"
-  titleText="Contact"
-  selectedId="0"
-  {items}
-  on:select={(e) => {
-    console.log(e.detail.selectedId);
-  }}
-  translateWithId={(id) => {
-    console.log(id); // "open" | "close"
-    return id;
-  }}
-  let:item
-  let:index
->
-  {item.id}
-  {index}
-</Dropdown>
-
-<Dropdown
-  itemToString={(item) => {
-    return item.text + " (" + item.id + ")";
-  }}
-  titleText="Contact"
-  selectedId="0"
-  items={itemsWithoutConst}
-/>
-
-<Dropdown
-  light
-  titleText="Contact"
-  selectedId="0"
-  items={[
-    { id: "0", text: "Slack" },
-    { id: "1", text: "Email" },
-    { id: "2", text: "Fax" },
-  ]}
-/>
-
-<Dropdown
-  type="inline"
-  titleText="Contact"
-  selectedId="0"
-  items={[
-    { id: "0", text: "Slack" },
-    { id: "1", text: "Email" },
-    { id: "2", text: "Fax" },
-  ]}
-/>
-
-<Dropdown
-  size="xl"
-  titleText="Contact"
-  selectedId="0"
-  items={[
-    { id: "0", text: "Slack" },
-    { id: "1", text: "Email" },
-    { id: "2", text: "Fax" },
-  ]}
-/>
-
-<Dropdown
-  size="sm"
-  titleText="Contact"
-  selectedId="0"
-  items={[
-    { id: "0", text: "Slack" },
-    { id: "1", text: "Email" },
-    { id: "2", text: "Fax" },
-  ]}
-/>
-
-<Dropdown
-  disabled
-  titleText="Contact"
-  selectedId="0"
-  items={[
-    { id: "0", text: "Slack" },
-    { id: "1", text: "Email" },
-    { id: "2", text: "Fax" },
-  ]}
-/>
-
-<DropdownSkeleton />
diff --git a/tests/Dropdown/Dropdown.test.svelte b/tests/Dropdown/Dropdown.test.svelte
new file mode 100644
index 00000000..6e5663f9
--- /dev/null
+++ b/tests/Dropdown/Dropdown.test.svelte
@@ -0,0 +1,53 @@
+<script lang="ts">
+  import { Dropdown } from "carbon-components-svelte";
+  import type { ComponentProps } from "svelte";
+
+  export let items: ComponentProps<Dropdown>["items"] = [];
+  export let itemToString: ComponentProps<Dropdown>["itemToString"] = undefined;
+  export let selectedId: ComponentProps<Dropdown>["selectedId"] = undefined;
+  export let type: ComponentProps<Dropdown>["type"] = "default";
+  export let direction: ComponentProps<Dropdown>["direction"] = "bottom";
+  export let size: ComponentProps<Dropdown>["size"] = undefined;
+  export let open: ComponentProps<Dropdown>["open"] = false;
+  export let light: ComponentProps<Dropdown>["light"] = false;
+  export let disabled: ComponentProps<Dropdown>["disabled"] = false;
+  export let titleText: ComponentProps<Dropdown>["titleText"] = "";
+  export let invalid: ComponentProps<Dropdown>["invalid"] = false;
+  export let invalidText: ComponentProps<Dropdown>["invalidText"] = "";
+  export let warn: ComponentProps<Dropdown>["warn"] = false;
+  export let warnText: ComponentProps<Dropdown>["warnText"] = "";
+  export let helperText: ComponentProps<Dropdown>["helperText"] = "";
+  export let label: ComponentProps<Dropdown>["label"] = undefined;
+  export let hideLabel: ComponentProps<Dropdown>["hideLabel"] = false;
+  export let translateWithId: ComponentProps<Dropdown>["translateWithId"] =
+    undefined;
+  export let id: ComponentProps<Dropdown>["id"] = "test-dropdown";
+  export let name: ComponentProps<Dropdown>["name"] = undefined;
+  export let ref: ComponentProps<Dropdown>["ref"] = null;
+</script>
+
+<Dropdown
+  {items}
+  {itemToString}
+  bind:selectedId
+  {type}
+  {direction}
+  {size}
+  bind:open
+  {light}
+  {disabled}
+  {titleText}
+  {invalid}
+  {invalidText}
+  {warn}
+  {warnText}
+  {helperText}
+  {label}
+  {hideLabel}
+  {translateWithId}
+  {id}
+  {name}
+  bind:ref
+  on:select
+  {...$$restProps}
+/>
diff --git a/tests/Dropdown/Dropdown.test.ts b/tests/Dropdown/Dropdown.test.ts
new file mode 100644
index 00000000..4154d81e
--- /dev/null
+++ b/tests/Dropdown/Dropdown.test.ts
@@ -0,0 +1,266 @@
+import { render, screen } from "@testing-library/svelte";
+import { user } from "../setup-tests";
+import Dropdown from "./Dropdown.test.svelte";
+import DropdownSlot from "./DropdownSlot.test.svelte";
+
+const items = [
+  { id: "0", text: "Slack" },
+  { id: "1", text: "Email" },
+  { id: "2", text: "Fax" },
+] as const;
+
+describe("Dropdown", () => {
+  it("should render with default props", () => {
+    render(Dropdown, {
+      props: { items, selectedId: "0", titleText: "Contact" },
+    });
+
+    expect(screen.getByText("Contact")).toBeInTheDocument();
+    const button = screen.getByRole("button");
+    expect(button.querySelector(".bx--list-box__label")).toHaveTextContent(
+      "Slack",
+    );
+  });
+
+  it("should handle custom item display text", () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+        titleText: "Contact",
+        itemToString: (item) => `${item.text} (${item.id})`,
+      },
+    });
+
+    const button = screen.getByRole("button");
+    expect(button.querySelector(".bx--list-box__label")).toHaveTextContent(
+      "Slack (0)",
+    );
+  });
+
+  it("should handle hidden label", () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+        titleText: "Contact",
+        hideLabel: true,
+      },
+    });
+
+    const label = screen.getByText("Contact");
+    expect(label).toHaveClass("bx--visually-hidden");
+  });
+
+  it("should handle light variant", () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+        light: true,
+      },
+    });
+
+    const button = screen.getByRole("button");
+    expect(button.closest(".bx--dropdown")).toHaveClass("bx--dropdown--light");
+  });
+
+  it("should handle inline variant", () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+        type: "inline",
+      },
+    });
+
+    const button = screen.getByRole("button");
+    expect(button).toBeEnabled();
+    expect(button).toHaveTextContent("Slack");
+    expect(button.closest(".bx--dropdown__wrapper")).toHaveClass(
+      "bx--dropdown__wrapper--inline",
+    );
+  });
+
+  it("should handle size variants", async () => {
+    const { rerender } = render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+        size: "sm",
+      },
+    });
+
+    const button = screen.getByRole("button");
+    expect(button.closest(".bx--dropdown")).toHaveClass("bx--dropdown--sm");
+
+    await rerender({ items, selectedId: "0", size: "xl" });
+    expect(button.closest(".bx--dropdown")).toHaveClass("bx--dropdown--xl");
+  });
+
+  it("should handle invalid state", () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+        invalid: true,
+        invalidText: "Invalid selection",
+      },
+    });
+
+    const button = screen.getByRole("button");
+    expect(button).toBeEnabled();
+    expect(button).toHaveTextContent("Slack");
+    expect(button.closest(".bx--dropdown")).toHaveAttribute(
+      "data-invalid",
+      "true",
+    );
+    expect(screen.getByText("Invalid selection")).toBeInTheDocument();
+  });
+
+  it("should handle warning state", () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+        warn: true,
+        warnText: "Warning message",
+      },
+    });
+
+    const button = screen.getByRole("button");
+    expect(button).toBeEnabled();
+    expect(button).toHaveTextContent("Slack");
+    expect(button.closest(".bx--dropdown")).toHaveClass(
+      "bx--dropdown--warning",
+    );
+    expect(screen.getByText("Warning message")).toBeInTheDocument();
+  });
+
+  it("should handle disabled state", () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+        disabled: true,
+      },
+    });
+
+    expect(screen.queryByRole("listbox")).not.toBeInTheDocument();
+    expect(screen.getByRole("button")).toHaveAttribute("disabled");
+    expect(screen.getByRole("button")).toHaveTextContent("Slack");
+  });
+
+  it("should handle helper text", () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+        helperText: "Help text",
+      },
+    });
+
+    expect(screen.getByText("Help text")).toHaveClass("bx--form__helper-text");
+  });
+
+  it("should handle item selection", async () => {
+    const { component } = render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+      },
+    });
+
+    const selectHandler = vi.fn();
+    component.$on("select", selectHandler);
+
+    const button = screen.getByRole("button");
+    await user.click(button);
+
+    const menuItemText = screen.getByText("Email");
+    const menuItem = menuItemText.closest(".bx--list-box__menu-item");
+    expect(menuItem).not.toBeNull();
+    await user.click(menuItem!);
+
+    expect(selectHandler).toHaveBeenCalledWith(
+      expect.objectContaining({
+        detail: { selectedId: "1", selectedItem: items[1] },
+      }),
+    );
+  });
+
+  it("should handle keyboard navigation", async () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+      },
+    });
+
+    const button = screen.getByRole("button");
+    await user.tab();
+    expect(button).toHaveFocus();
+
+    await user.keyboard("{Enter}");
+    expect(screen.getByRole("listbox")).toBeVisible();
+    expect(screen.getByRole("option", { selected: true })).toHaveTextContent(
+      "Slack",
+    );
+
+    await user.keyboard("{ArrowDown}{ArrowDown}");
+    await user.keyboard("{Enter}");
+
+    expect(screen.queryByRole("listbox")).not.toBeInTheDocument();
+    expect(button).toHaveTextContent("Email");
+  });
+
+  it("should handle disabled items", async () => {
+    const itemsWithDisabled = [
+      { id: "0", text: "Slack" },
+      { id: "1", text: "Email", disabled: true },
+      { id: "2", text: "Fax" },
+    ];
+
+    render(Dropdown, {
+      props: {
+        items: itemsWithDisabled,
+        selectedId: "0",
+      },
+    });
+
+    const button = screen.getByRole("button");
+    await user.click(button);
+
+    const menuItemText = screen.getByText("Email");
+    const menuItem = menuItemText.closest(".bx--list-box__menu-item");
+    expect(menuItem).not.toBeNull();
+    expect(menuItem).toHaveAttribute("disabled");
+  });
+
+  it("should handle custom slot content", async () => {
+    render(DropdownSlot);
+
+    await user.click(screen.getByRole("button"));
+
+    const customItems = screen.getAllByTestId("custom-item");
+    expect(customItems).toHaveLength(3);
+    expect(customItems[0]).toHaveTextContent("Item 1: Option 1");
+    expect(customItems[1]).toHaveTextContent("Item 2: Option 2");
+    expect(customItems[2]).toHaveTextContent("Item 3: Option 3");
+  });
+
+  it("should close on outside click", async () => {
+    render(Dropdown, {
+      props: {
+        items,
+        selectedId: "0",
+      },
+    });
+
+    await user.click(screen.getByRole("button"));
+    expect(screen.getByRole("listbox")).toBeVisible();
+
+    await user.click(document.body);
+    expect(screen.queryByRole("listbox")).not.toBeInTheDocument();
+  });
+});
diff --git a/tests/Dropdown/DropdownSlot.test.svelte b/tests/Dropdown/DropdownSlot.test.svelte
new file mode 100644
index 00000000..7be8caad
--- /dev/null
+++ b/tests/Dropdown/DropdownSlot.test.svelte
@@ -0,0 +1,25 @@
+<script lang="ts">
+  import { Dropdown } from "carbon-components-svelte";
+  import type { ComponentProps } from "svelte";
+
+  export let items: ComponentProps<Dropdown>["items"] = [
+    { id: "0", text: "Option 1" },
+    { id: "1", text: "Option 2" },
+    { id: "2", text: "Option 3" },
+  ];
+  export let selectedId: ComponentProps<Dropdown>["selectedId"] = "0";
+  export let id: ComponentProps<Dropdown>["id"] = "test-dropdown-slot";
+</script>
+
+<Dropdown
+  {items}
+  {selectedId}
+  {id}
+  titleText="Custom slot dropdown"
+  let:item
+  let:index
+>
+  <span data-testid="custom-item">
+    Item {index + 1}: {item.text}
+  </span>
+</Dropdown>