Add host validation to http request tests

This adds the ability for the http request tests to model assertions
on the host. This can be useful for asserting that the endpoint trait
is properly supported, as well as allowing for testing things like
AWS clients' ability to resolve hosts based on the service id and
region.

docs/source/1.0/spec/http-protocol-compliance-tests.rst

@@ -103,6 +103,17 @@ that support the following members:
       - ``string``
       - **Required**. The request-target of the HTTP request, not including
         the query string (for example, "/foo/bar").
+    * - host
+      - ``string``
+      - The host / endpoint provided to the client, not including the path or
+        scheme (for example, "example.com").
+    * - resolvedHost
+      - ``string``
+      - The host / endpoint that the client should send to, not including the
+        path or scheme (for example, "prefix.example.com").
+
+        This can differ from the host provided to the client if, for instance,
+        the operation has a member with the :ref:`endpoint-trait`.
     * - authScheme
       - shape ID
       - A shape ID that specifies the optional authentication scheme to

smithy-protocol-test-traits/src/main/java/software/amazon/smithy/protocoltests/traits/HttpRequestTestCase.java

@@ -17,6 +17,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 import software.amazon.smithy.model.node.ArrayNode;
 import software.amazon.smithy.model.node.Node;
 import software.amazon.smithy.model.node.ObjectNode;
@@ -32,12 +33,16 @@ public final class HttpRequestTestCase extends HttpMessageTestCase implements To
 
     private static final String METHOD = "method";
     private static final String URI = "uri";
+    private static final String HOST = "host";
+    private static final String RESOLVED_HOST = "resolvedHost";
     private static final String QUERY_PARAMS = "queryParams";
     private static final String FORBID_QUERY_PARAMS = "forbidQueryParams";
     private static final String REQUIRE_QUERY_PARAMS = "requireQueryParams";
 
     private final String method;
     private final String uri;
+    private final String host;
+    private final String resolvedHost;
     private final List<String> queryParams;
     private final List<String> forbidQueryParams;
     private final List<String> requireQueryParams;
@@ -46,6 +51,8 @@ private HttpRequestTestCase(Builder builder) {
         super(builder);
         method = SmithyBuilder.requiredState(METHOD, builder.method);
         uri = SmithyBuilder.requiredState(URI, builder.uri);
+        host = builder.host;
+        resolvedHost = builder.resolvedHost;
         queryParams = ListUtils.copyOf(builder.queryParams);
         forbidQueryParams = ListUtils.copyOf(builder.forbidQueryParams);
         requireQueryParams = ListUtils.copyOf(builder.requireQueryParams);
@@ -59,6 +66,14 @@ public String getUri() {
         return uri;
     }
 
+    public Optional<String> getHost() {
+        return Optional.ofNullable(host);
+    }
+
+    public Optional<String> getResolvedHost() {
+        return Optional.ofNullable(resolvedHost);
+    }
+
     public List<String> getQueryParams() {
         return queryParams;
     }
@@ -77,6 +92,8 @@ public static HttpRequestTestCase fromNode(Node node) {
         ObjectNode o = node.expectObjectNode();
         builder.method(o.expectStringMember(METHOD).getValue());
         builder.uri(o.expectStringMember(URI).getValue());
+        o.getStringMember(HOST).ifPresent(stringNode -> builder.host(stringNode.getValue()));
+        o.getStringMember(RESOLVED_HOST).ifPresent(stringNode -> builder.resolvedHost(stringNode.getValue()));
         o.getArrayMember(QUERY_PARAMS).ifPresent(queryParams -> {
             builder.queryParams(queryParams.getElementsAs(StringNode::getValue));
         });
@@ -94,6 +111,8 @@ public Node toNode() {
         ObjectNode.Builder node = super.toNode().expectObjectNode().toBuilder();
         node.withMember(METHOD, getMethod());
         node.withMember(URI, getUri());
+        node.withOptionalMember(HOST, getHost().map(StringNode::from));
+        node.withOptionalMember(RESOLVED_HOST, getResolvedHost().map(StringNode::from));
         if (!queryParams.isEmpty()) {
             node.withMember(QUERY_PARAMS, ArrayNode.fromStrings(getQueryParams()));
         }
@@ -114,6 +133,8 @@ public Builder toBuilder() {
                 .queryParams(getQueryParams())
                 .forbidQueryParams(getForbidQueryParams())
                 .requireQueryParams(getRequireQueryParams());
+        getHost().ifPresent(builder::host);
+        getResolvedHost().ifPresent(builder::resolvedHost);
         updateBuilder(builder);
         return builder;
     }
@@ -129,6 +150,8 @@ public static final class Builder extends HttpMessageTestCase.Builder<Builder, H
 
         private String method;
         private String uri;
+        private String host;
+        private String resolvedHost;
         private final List<String> queryParams = new ArrayList<>();
         private final List<String> forbidQueryParams = new ArrayList<>();
         private final List<String> requireQueryParams = new ArrayList<>();
@@ -145,6 +168,16 @@ public Builder uri(String uri) {
             return this;
         }
 
+        public Builder host(String host) {
+            this.host = host;
+            return this;
+        }
+
+        public Builder resolvedHost(String resolvedHost) {
+            this.resolvedHost = resolvedHost;
+            return this;
+        }
+
         public Builder queryParams(List<String> queryParams) {
             this.queryParams.clear();
             this.queryParams.addAll(queryParams);

smithy-protocol-test-traits/src/main/resources/META-INF/smithy/smithy.test.smithy

@@ -37,6 +37,17 @@ structure HttpRequestTestCase {
     @length(min: 1)
     uri: String,
 
+    /// The host / endpoint provided to the client, not including the path
+    /// or scheme (for example, "example.com").
+    host: String,
+
+    /// The host / endpoint that the client should send to, not including
+    /// the path or scheme (for example, "prefix.example.com").
+    ///
+    /// This can differ from the host provided to the client if the `hostPrefix`
+    /// member of the `endpoint` trait is set, for instance.
+    resolvedHost: String,
+
     /// The optional authentication scheme shape ID to assume. It's
     /// possible that specific authentication schemes might influence
     /// the serialization logic of an HTTP request.

smithy-protocol-test-traits/src/test/resources/software/amazon/smithy/protocoltests/traits/errorfiles/all-request-features.smithy

@@ -19,6 +19,8 @@ structure testScheme {}
         authScheme: testScheme,
         method: "POST",
         uri: "/",
+        host: "example.com",
+        resolvedHost: "prefix.example.com",
         queryParams: ["foo=baz"],
         forbidQueryParams: ["Nope"],
         requireQueryParams: ["Yap"],