DEV: improves sk api (#9653)

- reduces the API to 3 actions for now: appendContent/prependContent/onChange
- well tested
- removes all previous APIS which were only half supported or too dangerous as they could collide with other plugins or core behaviors
- this plugins also puts every sk test helpers in one file

test/javascripts/components/select-kit/api-test.js

@@ -0,0 +1,109 @@
+import componentTest from "helpers/component-test";
+import selectKit, {
+  testSelectKitModule,
+  setDefaultState,
+  DEFAULT_CONTENT
+} from "helpers/select-kit-helper";
+import { withPluginApi } from "discourse/lib/plugin-api";
+import { clearCallbacks } from "select-kit/mixins/plugin-api";
+
+testSelectKitModule("select-kit:api", {
+  beforeEach() {
+    this.setProperties({
+      comboBox: selectKit(".combo-box"),
+      singleSelect: selectKit(".single-select:not(.combo-box)")
+    });
+  },
+
+  afterEach() {
+    clearCallbacks();
+  }
+});
+
+componentTest("modifySelectKit(identifier).appendContent", {
+  template: `
+    {{combo-box value=value content=content onChange=onChange}}
+    {{single-select value=value content=content onChange=onChange}}
+  `,
+
+  beforeEach() {
+    setDefaultState(this, null, { content: DEFAULT_CONTENT });
+
+    withPluginApi("0.8.43", api => {
+      api.modifySelectKit("combo-box").appendContent(() => {
+        return {
+          id: "alpaca",
+          name: "Alpaca"
+        };
+      });
+    });
+  },
+
+  async test(assert) {
+    await this.comboBox.expand();
+    const row = this.comboBox.rowByIndex(3);
+    assert.ok(row.exists());
+    assert.equal(row.value(), "alpaca");
+
+    await this.comboBox.collapse();
+
+    assert.notOk(this.singleSelect.rowByValue("alpaca").exists());
+  }
+});
+
+componentTest("modifySelectKit(identifier).prependContent", {
+  template: `
+    {{combo-box value=value content=content onChange=onChange}}
+    {{single-select value=value content=content onChange=onChange}}
+  `,
+
+  beforeEach() {
+    setDefaultState(this, null, { content: DEFAULT_CONTENT });
+
+    withPluginApi("0.8.43", api => {
+      api.modifySelectKit("combo-box").prependContent(() => {
+        return {
+          id: "alpaca",
+          name: "Alpaca"
+        };
+      });
+    });
+  },
+
+  afterEach() {},
+
+  async test(assert) {
+    await this.comboBox.expand();
+    const row = this.comboBox.rowByIndex(0);
+    assert.ok(row.exists());
+    assert.equal(row.value(), "alpaca");
+
+    await this.comboBox.collapse();
+
+    assert.notOk(this.singleSelect.rowByValue("alpaca").exists());
+  }
+});
+
+componentTest("modifySelectKit(identifier).onChange", {
+  template: `
+    <div id="test"></div>
+    {{combo-box value=value content=content onChange=onChange}}
+  `,
+
+  beforeEach() {
+    setDefaultState(this, null, { content: DEFAULT_CONTENT });
+
+    withPluginApi("0.8.43", api => {
+      api.modifySelectKit("combo-box").onChange((component, value, item) => {
+        find("#test").text(item.name);
+      });
+    });
+  },
+
+  async test(assert) {
+    await this.comboBox.expand();
+    await this.comboBox.selectRowByIndex(0);
+
+    assert.equal(find("#test").text(), "foo");
+  }
+});