Polish "Improve exception message when subsection is empty array"

See gh-732

Author: wilkinsona

spring-restdocs-core/src/main/java/org/springframework/restdocs/payload/FieldPathPayloadSubsectionExtractor.java

@@ -93,7 +93,7 @@ public byte[] extractSubsection(byte[] payload, MediaType contentType, List<Fiel
 			if (value instanceof List) {
 				List<?> extractedList = (List<?>) value;
 				if (extractedList.isEmpty()) {
-					throw new PayloadHandlingException(this.fieldPath + " identifies a section of payload, but the section is empty");
+					throw new PayloadHandlingException(this.fieldPath + " identifies an empty section of the payload");
 				}
 				JsonContentHandler contentHandler = new JsonContentHandler(payload, descriptorsByPath.values());
 				Set<JsonFieldPath> uncommonPaths = JsonFieldPaths.from(extractedList).getUncommon().stream()

spring-restdocs-core/src/test/java/org/springframework/restdocs/payload/FieldPathPayloadSubsectionExtractorTests.java

@@ -184,11 +184,11 @@ public void extractNonExistentSubsection() throws JsonParseException, JsonMappin
 	}
 
 	@Test
-	public void extractEmptySubsection() throws JsonParseException, JsonMappingException, IOException {
+	public void extractEmptyArraySubsection() throws JsonParseException, JsonMappingException, IOException {
 		assertThatThrownBy(() -> new FieldPathPayloadSubsectionExtractor("a")
 				.extractSubsection("{\"a\":[]}}".getBytes(), MediaType.APPLICATION_JSON))
-				.isInstanceOf(PayloadHandlingException.class)
-				.hasMessage("a identifies a section of payload, but the section is empty");
+						.isInstanceOf(PayloadHandlingException.class)
+						.hasMessage("a identifies an empty section of the payload");
 	}
 
 }