Optional path and req param descriptors should count as documented

Previously, optional path and request parameter descriptors were ignored when checking that all of the parameters that are present had been documented. This lead to a false negative if a request or path parameter was present and was documented with an optional descriptor. This commit uses all of the descriptors, not just those that are not optional, when checking for undocumented parameters. Closes gh-228

Author: wilkinsona

spring-restdocs-core/src/main/java/org/springframework/restdocs/request/AbstractParametersSnippet.java

@@ -124,7 +124,7 @@ private void verifyParameterDescriptors(Operation operation) {
 }
 else {
 undocumentedParameters = new HashSet<>(actualParameters);
-undocumentedParameters.removeAll(expectedParameters);
+undocumentedParameters.removeAll(this.descriptorsByName.keySet());
 }
 Set<String> missingParameters = new HashSet<>(expectedParameters);
 missingParameters.removeAll(actualParameters);

spring-restdocs-core/src/test/java/org/springframework/restdocs/request/PathParametersSnippetTests.java

@@ -99,6 +99,24 @@ public void missingOptionalPathParameter() throws IOException {
 "/{a}").build());
 }
 
+@Test
+public void presentOptionalPathParameter() throws IOException {
+this.snippet
+.expectPathParameters(
+"present-optional-path-parameter")
+.withContents(tableWithTitleAndHeader(
+this.templateFormat == TemplateFormats.asciidoctor() ? "/{a}"
+: "`/{a}`",
+"Parameter", "Description").row("a", "one"));
+new PathParametersSnippet(
+Arrays.asList(parameterWithName("a").description("one").optional()))
+.document(operationBuilder("present-optional-path-parameter")
+.attribute(
+RestDocumentationGenerator.ATTRIBUTE_NAME_URL_TEMPLATE,
+"/{a}")
+.build());
+}
+
 @Test
 public void pathParametersWithQueryString() throws IOException {
 this.snippet.expectPathParameters("path-parameters-with-query-string")

spring-restdocs-core/src/test/java/org/springframework/restdocs/request/RequestParametersSnippetTests.java

@@ -104,6 +104,17 @@ public void missingOptionalRequestParameter() throws IOException {
 .build());
 }
 
+@Test
+public void presentOptionalRequestParameter() throws IOException {
+this.snippet.expectRequestParameters("present-optional-request-parameter")
+.withContents(
+tableWithHeader("Parameter", "Description").row("a", "one"));
+new RequestParametersSnippet(
+Arrays.asList(parameterWithName("a").description("one").optional()))
+.document(operationBuilder("present-optional-request-parameter")
+.request("http://localhost").param("a", "one").build());
+}
+
 @Test
 public void requestParametersWithCustomAttributes() throws IOException {
 TemplateResourceResolver resolver = mock(TemplateResourceResolver.class);