diff --git a/.travis.yml b/.travis.yml
index c640a566..c39264a2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@ install:
 matrix:
   fast_finish: true
 env:
-  - TEST_TYPE=bazel.build
+  - TEST_TYPE=bazel.test
 script: ./ci/ci_steps.sh
 
 branches:
diff --git a/api/rlds.proto b/api/rlds.proto
index 0b1f7692..b8fdb224 100644
--- a/api/rlds.proto
+++ b/api/rlds.proto
@@ -61,20 +61,6 @@ message RateLimitDescriptor {
   repeated Entry entries = 1;
 }
 
-// Defines an actual rate limit in terms of requests per unit of time and the unit itself.
-message RateLimit {
-  enum Unit {
-    UNKNOWN = 0;
-    SECOND  = 1;
-    MINUTE  = 2;
-    HOUR    = 3;
-    DAY     = 4;
-  }
-
-  uint32 requests_per_unit = 1;
-  Unit unit = 2;
-}
-
 // A response from a ShouldRateLimit call.
 message RateLimitResponse {
   enum Code {
@@ -83,6 +69,20 @@ message RateLimitResponse {
     OVER_LIMIT = 2;
   }
 
+  // Defines an actual rate limit in terms of requests per unit of time and the unit itself.
+  message RateLimit {
+    enum Unit {
+      UNKNOWN = 0;
+      SECOND  = 1;
+      MINUTE  = 2;
+      HOUR    = 3;
+      DAY     = 4;
+    }
+
+    uint32 requests_per_unit = 1;
+    Unit unit = 2;
+  }
+
   message DescriptorStatus {
     // The response code for an individual descriptor.
     Code code = 1;
diff --git a/ci/do_ci.sh b/ci/do_ci.sh
index 46b24328..49194d1c 100755
--- a/ci/do_ci.sh
+++ b/ci/do_ci.sh
@@ -8,9 +8,10 @@ set -e
 
 echo "building using ${NUM_CPUS} CPUs"
 
-if [[ "$1" == "bazel.build" ]]; then
-  echo "bazel build..."
+if [[ "$1" == "bazel.test" ]]; then
+  echo "bazel building and testing..."
   bazel --batch build ${BAZEL_BUILD_OPTIONS} //...
+  bazel --batch test ${BAZEL_TEST_OPTIONS} //...
   exit 0
 else
   echo "Invalid do_ci.sh target. The only valid target is bazel.build."
diff --git a/test/build/BUILD b/test/build/BUILD
new file mode 100644
index 00000000..681dacc4
--- /dev/null
+++ b/test/build/BUILD
@@ -0,0 +1,12 @@
+cc_test(
+    name = "build_test",
+    srcs = ["build_test.cc"],
+    deps = [
+        "//api:cds",
+        "//api:eds",
+        "//api:hds",
+        "//api:lds",
+        "//api:rlds",
+        "//api:rds",
+    ],
+)
diff --git a/test/build/build_test.cc b/test/build/build_test.cc
new file mode 100644
index 00000000..476fe075
--- /dev/null
+++ b/test/build/build_test.cc
@@ -0,0 +1,16 @@
+#include "api/cds.pb.h"
+#include "api/eds.pb.h"
+#include "api/hds.pb.h"
+#include "api/lds.pb.h"
+#include "api/rlds.pb.h"
+#include "api/rds.pb.h"
+
+// Basic C++ build/link validation for the v2 xDS APIs.
+int main(int argc, char *argv[]) {
+  envoy::api::v2::ClusterDiscoveryService::descriptor();
+  envoy::api::v2::EndpointDiscoveryService::descriptor();
+  envoy::api::v2::HealthDiscoveryService::descriptor();
+  envoy::api::v2::ListenerDiscoveryService::descriptor();
+  envoy::api::v2::RateLimitDiscoveryService::descriptor();
+  envoy::api::v2::RouteDiscoveryService::descriptor();
+}