Rename //testing/util to base (#3104)

Renaming per #3100

testing/base/test_raw_ostream_test.cpp

@@ -0,0 +1,63 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include "testing/base/test_raw_ostream.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+namespace Carbon::Testing {
+namespace {
+
+using ::testing::HasSubstr;
+using ::testing::StrEq;
+
+TEST(TestRawOstreamTest, Basics) {
+  TestRawOstream os;
+
+  os << "test 1";
+  EXPECT_THAT(os.TakeStr(), StrEq("test 1"));
+
+  os << "test"
+     << " "
+     << "2";
+  EXPECT_THAT(os.TakeStr(), StrEq("test 2"));
+
+  os << "test";
+  os << " ";
+  os << "3";
+  EXPECT_THAT(os.TakeStr(), StrEq("test 3"));
+}
+
+TEST(TestRawOstreamTest, MultipleStreams) {
+  TestRawOstream os1;
+  TestRawOstream os2;
+
+  os1 << "test ";
+  os2 << "test stream 2";
+  os1 << "stream 1";
+  EXPECT_THAT(os1.TakeStr(), StrEq("test stream 1"));
+  EXPECT_THAT(os2.TakeStr(), StrEq("test stream 2"));
+}
+
+TEST(TestRawOstreamTest, MultipleLines) {
+  TestRawOstream os;
+
+  os << "test line 1\n";
+  os << "test line 2\n";
+  os << "test line 3\n";
+  EXPECT_THAT(os.TakeStr(), StrEq("test line 1\ntest line 2\ntest line 3\n"));
+}
+
+TEST(TestRawOstreamTest, Substring) {
+  TestRawOstream os;
+
+  os << "test line 1\n";
+  os << "test line 2\n";
+  os << "test line 3\n";
+  EXPECT_THAT(os.TakeStr(), HasSubstr("test line 2"));
+}
+
+}  // namespace
+}  // namespace Carbon::Testing