Debugging aggregate to print selector

Author: RocketPuppy

API.md

@@ -315,6 +315,14 @@ printSelected: () => string[]
 
 Every test view has some default aggregate methods that are automatically provided.
 
+#### Print Selector
+
+Returns a string representation of the selector computed by the test view. This includes composed test views as well as any parameterization. Useful for debugging purposes. The method of stringifying is determined by the adapter.
+
+```typescript
+printSelector: () => string
+```
+
 #### Print Root
 
 Returns a string representation of the root element used to materialize the test view. Useful for debugging purposes. The method of stringifying is determined by the adapter.

README.md

@@ -90,7 +90,7 @@ all adapters.
 
 If a selector fails to select the required number of elements an error will be raised in the test. The error object includes more context about the error. The error messages should include a string representation of the selector, the root of the test view, and the selected elements.
 
-There are some default actions and aggregate methods useful for debugging tests with test views. A `printSelected` action is provided to return a string representation of the selected elements in a test view. A `printRoot` aggregate method is provided to return a string representation of the root of the test view.
+There are some default actions and aggregate methods useful for debugging tests with test views. A `printSelected` action is provided to return a string representation of the selected elements in a test view. A `printSelector` aggregate method is provided to return a string representation of the selector (including the result of any parameterization). A `printRoot` aggregate method is provided to return a string representation of the root of the test view.
 
 ## Contributing
 

core/index.test.ts

@@ -311,4 +311,16 @@ describe("Debugging failing selectors", () => {
 
 		expect(a.materialize("aba").printRoot()).toEqual("aba");
 	});
+
+	test("A printSelector aggregate can be used to see the string representation of the selector", () => {
+		const sel = testView("a")(testView("b"));
+
+		expect(sel.materialize("aba").printSelector()).toEqual("ab");
+	});
+
+	test("A printSelector aggregate can be used to see the string representation of the parameterized selector", () => {
+		const sel = testView(x => x + "a")(testView("b"));
+
+		expect(sel.materialize("aba", "foo").printSelector()).toEqual("fooab");
+	});
 });

core/index.ts

@@ -17,6 +17,7 @@ type AggregateParameters<E, A extends Aggregate<E>> = AParameters<A>;
 type AggregateMap<E> = { [k: string]: Aggregate<E> };
 type DefaultAggregates<E> = {
 	printRoot: (e: E[]) => string;
+	printSelector: (e: E[]) => string;
 };
 
 // Materialized aggregate types
@@ -131,6 +132,7 @@ const makeTestViewConstructor = <S, E>(
 	composeSelectors: ComposeSelectors<S>,
 	actionRealizer: ActionMaterializer<S, E>,
 	aggregateRealizer: AggregateMaterializer<S, E>,
+	printSelector: Printer<S>,
 	printElement: Printer<E>,
 	defaultViews: DefaultViews<S, E>
 ): TestViewConstructor<S, E> => {
@@ -208,6 +210,11 @@ const makeTestViewConstructor = <S, E>(
 				E,
 				DefaultAggregates<E>
 			> = {
+				printSelector: aggregateRealizer(
+					renderedSelector,
+					() => printSelector(renderedSelector),
+					root
+				),
 				printRoot: aggregateRealizer(
 					renderedSelector,
 					() => printElement(root),
@@ -474,6 +481,7 @@ export const makeAdapter = <S, E, EG>(
 			printElement
 		),
 		makeAggregateRealizer<S, E, EG>(runSelector, iterateSelector),
+		printSelector,
 		printElement,
 		defaultViews
 	);