Revise JSON path options in GraphQlTester

Closes gh-278

Author: rstoyanchev

spring-graphql-test/src/main/java/org/springframework/graphql/test/tester/DefaultGraphQlTester.java

@@ -34,11 +34,11 @@
 
 import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.core.ResolvableType;
-import org.springframework.graphql.support.DefaultGraphQlRequest;
 import org.springframework.graphql.GraphQlRequest;
 import org.springframework.graphql.GraphQlResponse;
 import org.springframework.graphql.ResponseError;
 import org.springframework.graphql.client.GraphQlTransport;
+import org.springframework.graphql.support.DefaultGraphQlRequest;
 import org.springframework.graphql.support.DocumentSource;
 import org.springframework.lang.Nullable;
 import org.springframework.test.util.AssertionErrors;
@@ -377,38 +377,25 @@ public Path path(String path) {
 		}
 
 		@Override
-		public Path pathExists() {
-			this.delegate.doAssert(() -> this.pathHelper.hasJsonPath(this.delegate.jsonContent()));
-			return this;
-		}
-
-		@Override
-		public Path pathDoesNotExist() {
-			this.delegate.doAssert(() -> this.pathHelper.doesNotHaveJsonPath(this.delegate.jsonContent()));
-			return this;
-		}
-
-		@Override
-		public Path valueExists() {
+		public Path hasValue() {
 			this.delegate.doAssert(() -> this.pathHelper.exists(this.delegate.jsonContent()));
 			return this;
 		}
 
 		@Override
-		public Path valueDoesNotExist() {
-			this.delegate.doAssert(() -> this.pathHelper.doesNotExist(this.delegate.jsonContent()));
-			return this;
-		}
-
-		@Override
-		public Path valueIsEmpty() {
-			this.delegate.doAssert(() -> this.pathHelper.assertValueIsEmpty(this.delegate.jsonContent()));
+		public Path valueIsNull() {
+			Assert.isTrue(this.jsonPath.isDefinite(), "isNull applies only to JSONPath targeting a single value");
+			this.delegate.doAssert(() -> {
+				Object value = this.pathHelper.evaluateJsonPath(this.delegate.jsonContent());
+				AssertionErrors.assertNull(
+						"Expected null value at JSON path \"" + path + "\" but found " + value, value);
+			});
 			return this;
 		}
 
 		@Override
-		public Path valueIsNotEmpty() {
-			this.delegate.doAssert(() -> this.pathHelper.assertValueIsNotEmpty(this.delegate.jsonContent()));
+		public Path pathDoesNotExist() {
+			this.delegate.doAssert(() -> this.pathHelper.doesNotHaveJsonPath(this.delegate.jsonContent()));
 			return this;
 		}
 

spring-graphql-test/src/main/java/org/springframework/graphql/test/tester/GraphQlTester.java

@@ -213,43 +213,21 @@ interface Response extends Traversable {
 	interface Path extends Traversable {
 
 		/**
-		 * Verify the given path exists, even if the value is {@code null}.
+		 * Verify there is a {@code non-null} value or a non-empty list at the current path.
 		 * @return the same {@code Path} spec for further assertions
 		 */
-		Path pathExists();
+		Path hasValue();
 
 		/**
-		 * Assert the given path does not {@link #pathExists() exist}.
-		 * @return the same {@code Path} spec for further assertions
-		 */
-		Path pathDoesNotExist();
-
-		/**
-		 * Assert a value exists at the given path where the value is any {@code non-null}
-		 * value, possibly an empty array or map.
-		 * @return the same {@code Path} spec for further assertions
+		 * Verify there is a {@code null} value at the current path.
 		 */
-		Path valueExists();
+		Path valueIsNull();
 
 		/**
-		 * Assert a value does not {@link #valueExists() exist} at the given path.
+		 * Verify the current path does not exist.
 		 * @return the same {@code Path} spec for further assertions
 		 */
-		Path valueDoesNotExist();
-
-		/**
-		 * Assert the value at the given path does exist but is empty as defined
-		 * in {@link org.springframework.util.ObjectUtils#isEmpty(Object)}.
-		 * @return the same {@code Path} spec for further assertions
-		 * @see org.springframework.util.ObjectUtils#isEmpty(Object)
-		 */
-		Path valueIsEmpty();
-
-		/**
-		 * Assert the value at the given path is not {@link #valueIsEmpty() empty}.
-		 * @return the same {@code Path} spec for further assertions
-		 */
-		Path valueIsNotEmpty();
+		Path pathDoesNotExist();
 
 		/**
 		 * Convert the data at the given path to the target type.

spring-graphql-test/src/test/java/org/springframework/graphql/test/tester/GraphQlTesterTests.java

@@ -40,38 +40,61 @@
 public class GraphQlTesterTests extends GraphQlTesterTestSupport {
 
 	@Test
-	void pathAndValueExist() {
+	void hasValue() {
 
 		String document = "{me {name, friends}}";
 		setMockResponse("{\"me\": {\"name\":\"Luke Skywalker\", \"friends\":[]}}");
 
 		GraphQlTester.Response response = graphQlTester().document(document).execute();
+		response.path("me.name").hasValue();
+		response.path("me.friends").hasValue();
 
-		response.path("me.name").pathExists().valueExists();
-		response.path("me.friends").pathExists().valueExists();
-		response.path("hero").pathDoesNotExist().valueDoesNotExist();
+		assertThatThrownBy(() -> response.path("hero").hasValue())
+				.hasMessageContaining("No value at JSON path \"$['data']['hero']");
 
 		assertThat(request().getDocument()).contains(document);
 	}
 
 	@Test
-	void valueIsEmpty() {
+	void valueIsNull() {
 
 		String document = "{me {name, friends}}";
-		setMockResponse("{\"me\": {\"name\":null, \"friends\":[]}}");
+		setMockResponse("{\"me\": {\"name\":null, \"friends\":null}}");
 
 		GraphQlTester.Response response = graphQlTester().document(document).execute();
 
-		response.path("me.name").valueIsEmpty();
-		response.path("me.friends").valueIsEmpty();
+		response.path("me.name").valueIsNull();
+		response.path("me.friends").valueIsNull();
 
-		assertThatThrownBy(() -> response.path("hero").valueIsEmpty())
-				.as("Path does not even exist")
-				.hasMessageContaining("No value at JSON path \"$['data']['hero']");
+		assertThatThrownBy(() -> response.path("me").valueIsNull())
+				.hasMessageContaining("Expected null value at JSON path");
 
 		assertThat(request().getDocument()).contains(document);
 	}
 
+	@Test
+	void valueIsEmptyList() {
+
+		String document = "{me {name, friends}}";
+		setMockResponse("{\"me\": {\"name\":\"Luke Skywalker\", \"friends\":[]}}");
+
+		GraphQlTester.Response response = graphQlTester().document(document).execute();
+		response.path("me.friends").hasValue().entityList(MovieCharacter.class).hasSize(0);
+	}
+
+	@Test
+	void pathDoesNotExist() {
+		String document = "{me {name, friends}}";
+		setMockResponse("{\"me\": {\"name\":\"Luke Skywalker\", \"friends\":[]}}");
+
+		GraphQlTester.Response response = graphQlTester().document(document).execute();
+
+		response.path("hero").pathDoesNotExist();
+
+		assertThatThrownBy(() -> response.path("me.name").pathDoesNotExist())
+				.hasMessageContaining("Expected no value at JSON path");
+	}
+
 	@Test
 	void matchesJson() {