feat: ability to peek at current responses

Closes: #4

Author: nergal-perm

src/main/java/ewc/utilities/testableio/core/GenericIoStub.java

@@ -52,9 +52,7 @@ public class GenericIoStub {
     private final Set<Stub> stored = new HashSet<>();
 
     public GenericResponse nextResponseFor(final ClientId client, final QueryId query) {
-        return this.stubs
-            .getOrDefault(client, this.stubs.get(GenericIoStub.COMMON_CLIENT))
-            .nextResponseFor(query);
+        return this.stubsForClient(client).nextResponseFor(query);
     }
 
     /**
@@ -109,14 +107,27 @@ public void setActiveResponse(
                 });
     }
 
+    public Map<QueryId, GenericResponse> getCurrentCommonStubs() {
+        return this.stubs.get(GenericIoStub.COMMON_CLIENT).currentActive();
+    }
+
+    public Map<QueryId, GenericResponse> getCurrentClientStubs(final ClientId client) {
+        final Map<QueryId, GenericResponse> result = new HashMap<>(
+            this.stubs.get(GenericIoStub.COMMON_CLIENT).currentActive()
+        );
+        result.putAll(this.stubsForClient(client).currentActive());
+        return result;
+    }
+
     /**
      * Sets the active response for a specific client.
      *
      * @param client The client ID for which the response is to be set.
      * @param stub The response to be set as active.
      */
     private void setActiveResponse(final ClientId client, final Stub stub) {
-        this.getStubsFor(client).setSingleResponseFor(stub.query(), stub.response());
+        this.stubs.putIfAbsent(client, new SingleClientStubs());
+        this.stubs.get(client).setSingleResponseFor(stub.query(), stub.response());
     }
 
     /**
@@ -127,11 +138,10 @@ private void setActiveResponse(final ClientId client, final Stub stub) {
      */
     private void addStub(final Stub stub, final ClientId client) {
         this.stored.add(stub);
-        this.getStubsFor(client).setSingleResponseFor(stub.query(), stub.response());
+        this.setActiveResponse(client, stub);
     }
 
-    private SingleClientStubs getStubsFor(final ClientId client) {
-        this.stubs.putIfAbsent(client, new SingleClientStubs());
-        return this.stubs.get(client);
+    private SingleClientStubs stubsForClient(ClientId client) {
+        return this.stubs.getOrDefault(client, this.stubs.get(GenericIoStub.COMMON_CLIENT));
     }
 }

src/main/java/ewc/utilities/testableio/core/SingleClientStubs.java

@@ -59,4 +59,12 @@ public GenericResponse nextResponseFor(QueryId query) {
         }
         return response;
     }
+
+    public Map<QueryId, GenericResponse> currentActive() {
+        final Map<QueryId, GenericResponse> active = new HashMap<>(this.stubs.size());
+        this.stubs.keySet().forEach(query -> {
+            active.put(query, this.stubs.get(query).peek());
+        });
+        return active;
+    }
 }

src/main/java/ewc/utilities/testableio/core/SingleQueryResponses.java

@@ -26,6 +26,7 @@
 
 import java.util.NoSuchElementException;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Supplier;
 
 /**
  * This class provides configured responses for a single I/O operation stub. The responses could
@@ -96,6 +97,24 @@ private SingleQueryResponses(
      * @return The next configured response.
      */
     public GenericResponse next() {
+        final GenericResponse value = responseUsing(this.index::getAndIncrement);
+        if (value.contents() instanceof RuntimeException runtimeException) {
+            throw runtimeException;
+        }
+        return value;
+    }
+
+    /**
+     * Returns the next configured response without "removing" it from responses queue.
+     * If the queue is already exhausted, a {@link NoSuchElementException} will be thrown.
+     *
+     * @return The next configured response.
+     */
+    public GenericResponse peek() {
+        return responseUsing(this.index::currentValue);
+    }
+
+    private GenericResponse responseUsing(Supplier<Integer> counter) {
         if (this.values == null) {
             throw new IllegalStateException("No response to send");
         }
@@ -104,11 +123,7 @@ public GenericResponse next() {
                 String.format("No more configured responses for %s", this.description)
             );
         }
-        final GenericResponse value = this.values[this.index.getAndIncrement()];
-        if (value.contents() instanceof RuntimeException runtimeException) {
-            throw runtimeException;
-        }
-        return value;
+        return this.values[counter.get()];
     }
 
     /**

src/test/java/ewc/utilities/testableio/external/EndToEndTest.java

@@ -25,6 +25,7 @@
 package ewc.utilities.testableio.external;
 
 import ewc.utilities.testableio.core.*;
+import java.util.Map;
 import java.util.stream.Stream;
 import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
@@ -43,10 +44,11 @@ final class EndToEndTest {
     public static final ClientId ANY_CLIENT = new ClientId("any client");
     public static final ClientId VIP_CLIENT = new ClientId("VIP client");
     public static final ClientId NEW_CLIENT = new ClientId("new client");
+    public static final IllegalStateException NO_SUCH_PAGE_EXCEPTION = new IllegalStateException("no such page");
     public static final GenericResponse DEFAULT_HOME_PAGE = new GenericResponse("html for the home page");
     public static final GenericResponse DEFAULT_NUMBER_PAGE = new GenericResponse(1000L);
-    public static final IllegalStateException NO_SUCH_PAGE = new IllegalStateException("no such page");
     public static final GenericResponse VIP_HOME_PAGE = new GenericResponse("VIP home page");
+    public static final GenericResponse NO_SUCH_PAGE = new GenericResponse(NO_SUCH_PAGE_EXCEPTION);
     private GenericIoStub target;
 
     @BeforeEach
@@ -57,7 +59,7 @@ void setUp() {
                 .withContents(DEFAULT_HOME_PAGE)
                 .withResponseId("home"),
             Stub.forQueryId("non-existing")
-                .withContents(new GenericResponse(NO_SUCH_PAGE))
+                .withContents(NO_SUCH_PAGE)
                 .withResponseId("non-existing"),
             Stub.forQueryId("number")
                 .withContents(DEFAULT_NUMBER_PAGE)
@@ -73,9 +75,9 @@ void shouldHaveAPredefinedSetOfDefaultResponses() {
         when(ANY_CLIENT).requests(NUMBER_PAGE).then(DEFAULT_NUMBER_PAGE);
         when(NEW_CLIENT).requests(NUMBER_PAGE).then(DEFAULT_NUMBER_PAGE);
         when(VIP_CLIENT).requests(NUMBER_PAGE).then(DEFAULT_NUMBER_PAGE);
-        when(ANY_CLIENT).requests(MISSING_PAGE).thenThrows(NO_SUCH_PAGE);
-        when(NEW_CLIENT).requests(MISSING_PAGE).thenThrows(NO_SUCH_PAGE);
-        when(VIP_CLIENT).requests(MISSING_PAGE).thenThrows(NO_SUCH_PAGE);
+        when(ANY_CLIENT).requests(MISSING_PAGE).thenThrows(NO_SUCH_PAGE_EXCEPTION);
+        when(NEW_CLIENT).requests(MISSING_PAGE).thenThrows(NO_SUCH_PAGE_EXCEPTION);
+        when(VIP_CLIENT).requests(MISSING_PAGE).thenThrows(NO_SUCH_PAGE_EXCEPTION);
     }
 
     @Test
@@ -106,6 +108,25 @@ void shouldChooseActiveStubFromStoredStubs() {
         when(ANY_CLIENT).requests(HOME_PAGE).then(DEFAULT_HOME_PAGE);
     }
 
+    @Test
+    void shouldReturnCorrectCommonState() {
+        final Map<QueryId, GenericResponse> actual = this.target.getCurrentCommonStubs();
+        Assertions.assertThat(actual)
+            .containsEntry(HOME_PAGE, DEFAULT_HOME_PAGE)
+            .containsEntry(NUMBER_PAGE, DEFAULT_NUMBER_PAGE)
+            .containsEntry(MISSING_PAGE, NO_SUCH_PAGE);
+    }
+
+    @Test
+    void shouldCombineCommonAndClientCurrentState() {
+        final Stub newHome = Stub.forQueryId("home").withContents(VIP_HOME_PAGE).withResponseId("home");
+        this.target.addClientStub(newHome, VIP_CLIENT);
+        final Map<QueryId, GenericResponse> actual = this.target.getCurrentClientStubs(VIP_CLIENT);
+        Assertions.assertThat(actual)
+            .containsEntry(HOME_PAGE, VIP_HOME_PAGE)
+            .containsEntry(NUMBER_PAGE, DEFAULT_NUMBER_PAGE)
+            .containsEntry(MISSING_PAGE, NO_SUCH_PAGE);
+    }
 
     private When when(ClientId client) {
         return new When(client);