add storybook example and jest tests

Author: haschek

src/cmem/ContentBlobToggler/stories/StringPreviewContentBlobToggler.stories.tsx

@@ -0,0 +1,27 @@
+import React from "react";
+import { Meta, StoryFn } from "@storybook/react";
+
+import { Markdown, StringPreviewContentBlobToggler } from "../../../index";
+
+const config = {
+    title: "CMEM/ContentBlobToggler/StringPreview",
+    component: StringPreviewContentBlobToggler,
+} as Meta<typeof StringPreviewContentBlobToggler>;
+export default config;
+
+const Template: StoryFn<typeof StringPreviewContentBlobToggler> = (args) => (
+    <StringPreviewContentBlobToggler {...args} />
+);
+
+const initialTeststring =
+    "A library for GUI elements.\nIn order to create graphical user interfaces, please have look at the documentation at [Github](https://github.com/eccenca/gui-elements).";
+
+export const Default = Template.bind({});
+Default.args = {
+    content: initialTeststring,
+    fullviewContent: <Markdown htmlContentBlockProps={{ large: true }}>{initialTeststring}</Markdown>,
+    previewMaxLength: 64,
+    renderPreviewAsMarkdown: true,
+    toggleExtendText: "show more",
+    toggleReduceText: "show less",
+};

src/cmem/ContentBlobToggler/tests/StringPreviewContentBlobToggler.test.tsx

@@ -0,0 +1,98 @@
+import React from "react";
+import { render, RenderResult } from "@testing-library/react";
+
+import "@testing-library/jest-dom";
+
+import {
+    StringPreviewContentBlobToggler,
+    StringPreviewContentBlobTogglerProps,
+} from "../StringPreviewContentBlobToggler";
+
+import { Default as StringPreviewContentBlobTogglerStory } from "./../stories/StringPreviewContentBlobToggler.stories";
+
+describe("StringPreviewContentBlobToggler", () => {
+    const textMustExist = (queryByText: RenderResult["queryByText"], text: string) => {
+        expect(queryByText(text, { exact: false })).not.toBeNull();
+    };
+    const textMustNotExist = (queryByText: RenderResult["queryByText"], text: string) => {
+        expect(queryByText(text, { exact: false })).toBeNull();
+    };
+    it("should cut preview and show toggler to extend", () => {
+        const { queryByText } = render(
+            <StringPreviewContentBlobToggler
+                {...(StringPreviewContentBlobTogglerStory.args as StringPreviewContentBlobTogglerProps)}
+            />
+        );
+        textMustExist(queryByText, "A library for GUI elements.");
+        textMustNotExist(
+            queryByText,
+            "In order to create graphical user interfaces, please have look at the documentation at"
+        );
+        textMustExist(queryByText, "show more");
+    });
+    it("should display full view if `startExtended` is enabled, and show toggler to reduce", () => {
+        const { queryByText } = render(
+            <StringPreviewContentBlobToggler
+                {...(StringPreviewContentBlobTogglerStory.args as StringPreviewContentBlobTogglerProps)}
+                startExtended
+            />
+        );
+        textMustExist(
+            queryByText,
+            "In order to create graphical user interfaces, please have look at the documentation at"
+        );
+        textMustExist(queryByText, "show less");
+    });
+    it('should display only first content line on `useOnly={"firstNonEmptyLine"}`', () => {
+        const { queryByText } = render(
+            <StringPreviewContentBlobToggler
+                {...(StringPreviewContentBlobTogglerStory.args as StringPreviewContentBlobTogglerProps)}
+                useOnly={"firstNonEmptyLine"}
+            />
+        );
+        textMustExist(queryByText, "A library for GUI elements.");
+        textMustNotExist(queryByText, "In order to create");
+    });
+    it('should use first Markdown paragraph as preview content on `useOnly={"firstMarkdownSection"}` but shorten it', () => {
+        const { queryByText } = render(
+            <StringPreviewContentBlobToggler
+                {...(StringPreviewContentBlobTogglerStory.args as StringPreviewContentBlobTogglerProps)}
+                useOnly={"firstMarkdownSection"}
+            />
+        );
+        textMustExist(queryByText, "A library for GUI elements.");
+        textMustExist(queryByText, "In order to create");
+        textMustNotExist(queryByText, "please have look at the documentation at");
+    });
+    it("should display full preview and no toggler if content is short enough", () => {
+        const { queryByText } = render(
+            <StringPreviewContentBlobToggler
+                {...(StringPreviewContentBlobTogglerStory.args as StringPreviewContentBlobTogglerProps)}
+                previewMaxLength={144}
+            />
+        );
+        textMustExist(queryByText, "A library for GUI elements.");
+        textMustExist(
+            queryByText,
+            "In order to create graphical user interfaces, please have look at the documentation at"
+        );
+        textMustNotExist(queryByText, "https://github.com/"); // test if Markdown was rendered
+        textMustNotExist(queryByText, "show more");
+    });
+    it("should not use Markdown rendering on `renderPreviewAsMarkdown={false}`", () => {
+        const { queryByText } = render(
+            <StringPreviewContentBlobToggler
+                {...(StringPreviewContentBlobTogglerStory.args as StringPreviewContentBlobTogglerProps)}
+                previewMaxLength={144}
+                renderPreviewAsMarkdown={false}
+            />
+        );
+        textMustExist(queryByText, "A library for GUI elements.");
+        textMustExist(
+            queryByText,
+            "In order to create graphical user interfaces, please have look at the documentation at"
+        );
+        textMustExist(queryByText, "https://github.com/"); // test if Markdown was rendered
+        textMustExist(queryByText, "show more");
+    });
+});