search: Add some tests for instrumentation.js

Change I45dda26cb5 removes some code, and in the process reduces the
branch coverage of the skins.vector.search module below the threshold of
25% that CI requires; add some tests for instrumentation.js to bring the
branch coverage up again.

Change-Id: I5d7ae019b3219b410c658583a6d72cf56d0cc1c5

tests/jest/instrumentation.test.js

@@ -0,0 +1,24 @@
+const instrumentation = require( '../../resources/skins.vector.search/instrumentation.js' );
+
+describe( 'instrumentation', () => {
+	test.each( [
+		[ 0, 'acrw10' ],
+		[ 1, 'acrw11' ],
+		[ -1, 'acrw1' ]
+	] )( 'getWprovFromResultIndex( %d ) = %s', ( index, expected ) => {
+		expect( instrumentation.getWprovFromResultIndex( index ) )
+			.toBe( expected );
+	} );
+
+	describe( 'generateUrl', () => {
+		test.each( [
+			[ 'string', 'title' ],
+			[ 'object', { title: 'title' } ]
+		] )( 'should generate URL from %s', ( _name, suggestion ) => {
+			const meta = { index: 1 };
+			expect( instrumentation.generateUrl( suggestion, meta ) )
+				// mw-node-qunit provides a pretty weird mw.Uri.toString()...
+				.toBe( 'https://host?title=suggestion=wprov' );
+		} );
+	} );
+} );