bug: restore samples to the Bazel builds. (#614)

I accidentally removed the samples from the Bazel builds, this change
restores them.

Author: coryan

google/cloud/spanner/samples/BUILD

@@ -18,7 +18,8 @@ package(default_visibility = ["//visibility:public"])
 
 licenses(["notice"])  # Apache 2.0
 
-load(":spanner_client_samples.bzl", "spanner_client_samples")
+load(":spanner_client_integration_samples.bzl", "spanner_client_integration_samples")
+load(":spanner_client_unit_samples.bzl", "spanner_client_unit_samples")
 
 [cc_test(
     name = "spanner_client_" + test.replace("/", "_").replace(".cc", ""),
@@ -31,4 +32,16 @@ load(":spanner_client_samples.bzl", "spanner_client_samples")
         "@com_github_googleapis_google_cloud_cpp//google/cloud/testing_util:google_cloud_cpp_testing",
         "@com_google_googletest//:gtest",
     ],
-) for test in spanner_client_samples]
+) for test in spanner_client_integration_samples]
+
+[cc_test(
+    name = "spanner_client_" + test.replace("/", "_").replace(".cc", ""),
+    srcs = [test],
+    deps = [
+        "//google/cloud/spanner:spanner_client",
+        "//google/cloud/spanner:spanner_client_testing",
+        "@com_github_googleapis_google_cloud_cpp//google/cloud:google_cloud_cpp_common",
+        "@com_github_googleapis_google_cloud_cpp//google/cloud/testing_util:google_cloud_cpp_testing",
+        "@com_google_googletest//:gtest",
+    ],
+) for test in spanner_client_unit_samples]

google/cloud/spanner/samples/CMakeLists.txt

@@ -35,7 +35,10 @@ function (spanner_client_define_samples)
 
     # Export the list of unit tests to a .bzl file so we do not need to maintain
     # the list in two places.
-    export_list_to_bazel("spanner_client_samples.bzl" "spanner_client_samples")
+    export_list_to_bazel("spanner_client_integration_samples.bzl"
+                         "spanner_client_integration_samples")
+    export_list_to_bazel("spanner_client_unit_samples.bzl"
+                         "spanner_client_unit_samples")
 
     # Generate a target for each unit test.
     foreach (fname ${spanner_client_integration_samples}

google/cloud/spanner/samples/spanner_client_samples.bzl renamed to google/cloud/spanner/samples/spanner_client_integration_samples.bzl

@@ -16,5 +16,6 @@
 
 """Automatically generated unit tests list - DO NOT EDIT."""
 
-spanner_client_samples = [
+spanner_client_integration_samples = [
+    "samples.cc",
 ]

google/cloud/spanner/samples/spanner_client_unit_samples.bzl

@@ -0,0 +1,21 @@
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# DO NOT EDIT -- GENERATED BY CMake -- Change the CMakeLists.txt file if needed
+
+"""Automatically generated unit tests list - DO NOT EDIT."""
+
+spanner_client_unit_samples = [
+    "mock_execute_sql.cc",
+]