ComboboxControl: Add more unit tests (#65255)

* Combobox Control: Do not clear values when focusing the textbox

* Call onFilterValueChange on blur if no value is selected

* Clear inputValue on the background to avoid suggestion flickering

* Revert "Clear inputValue on the background to avoid suggestion flickering"

This reverts commit 43158d2.

* Revert "Call onFilterValueChange on blur if no value is selected"

This reverts commit 2a62872.

* Revert "Combobox Control: Do not clear values when focusing the textbox"

This reverts commit 0423a7e.

* Tweak tests

---------

Co-authored-by: Lena Morita <[email protected]>
Co-authored-by: zaguiini <[email protected]>
Co-authored-by: mirka <[email protected]>
Co-authored-by: tyxla <[email protected]>

packages/components/src/combobox-control/test/index.tsx

@@ -188,6 +188,46 @@ describe.each( [
 		expect( input ).toHaveValue( targetOption.label );
 	} );
 
+	it( 'calls onFilterValueChange whenever the textbox changes', async () => {
+		const user = userEvent.setup();
+		const onFilterValueChangeSpy = jest.fn();
+		render(
+			<Component
+				options={ timezones }
+				label={ defaultLabelText }
+				onFilterValueChange={ onFilterValueChangeSpy }
+			/>
+		);
+
+		const input = getInput( defaultLabelText );
+
+		await user.type( input, 'a' );
+		expect( onFilterValueChangeSpy ).toHaveBeenCalledWith( 'a' );
+	} );
+
+	it( 'clears the textbox value if there is no selected value on blur', async () => {
+		const user = userEvent.setup();
+		const onFilterValueChangeSpy = jest.fn();
+		render(
+			<Component
+				options={ timezones }
+				label={ defaultLabelText }
+				onFilterValueChange={ onFilterValueChangeSpy }
+			/>
+		);
+		const input = getInput( defaultLabelText );
+
+		await user.type( input, 'a' );
+		expect( input ).toHaveValue( 'a' );
+
+		// Blur and focus the input.
+		await user.tab();
+		await user.click( input );
+
+		expect( input ).toHaveValue( '' );
+		expect( onFilterValueChangeSpy ).toHaveBeenLastCalledWith( '' );
+	} );
+
 	it( 'should select the correct option from a search', async () => {
 		const user = await userEvent.setup();
 		const targetOption = timezones[ 13 ];