CdkSelection: Add unit tests

Author: yifange

src/cdk-experimental/selection/BUILD.bazel

@@ -1,6 +1,6 @@
 package(default_visibility = ["//visibility:public"])
 
-load("//tools:defaults.bzl", "ng_module")
+load("//tools:defaults.bzl", "ng_module", "ng_test_library", "ng_web_test_suite")
 
 ng_module(
     name = "selection",
@@ -18,3 +18,21 @@ ng_module(
         "@npm//rxjs",
     ],
 )
+
+ng_test_library(
+    name = "unit_test_sources",
+    srcs = glob(
+        ["**/*.spec.ts"],
+        exclude = ["**/*.e2e.spec.ts"],
+    ),
+    deps = [
+        ":selection",
+        "//src/cdk/table",
+        "//src/cdk/testing/private",
+    ],
+)
+
+ng_web_test_suite(
+    name = "unit_tests",
+    deps = [":unit_test_sources"],
+)