diff --git a/libs/gui/tests/GLTest.cpp b/libs/gui/tests/GLTest.cpp
index 3ae4b6d..9024b70 100644
--- a/libs/gui/tests/GLTest.cpp
+++ b/libs/gui/tests/GLTest.cpp
@@ -185,7 +185,7 @@
         while ((err = glGetError()) != GL_NO_ERROR) {
             msg += String8::format(", %#x", err);
         }
-        return ::testing::AssertionFailure(::testing::Message(msg.string()));
+        return ::testing::AssertionFailure(::testing::Message(msg.c_str()));
     }
     if (r >= 0 && abs(r - int(pixel[0])) > tolerance) {
         msg += String8::format("r(%d isn't %d)", pixel[0], r);
@@ -209,7 +209,7 @@
         msg += String8::format("a(%d isn't %d)", pixel[3], a);
     }
     if (!msg.isEmpty()) {
-        return ::testing::AssertionFailure(::testing::Message(msg.string()));
+        return ::testing::AssertionFailure(::testing::Message(msg.c_str()));
     } else {
         return ::testing::AssertionSuccess();
     }
@@ -244,8 +244,8 @@
         msg += String8::format(" R1: [%d %d %d %d] R2: [%d %d %d %d]",
                                r1.left, r1.top, r1.right, r1.bottom,
                                r2.left, r2.top, r2.right, r2.bottom);
-        fprintf(stderr, "assertRectEq: %s\n", msg.string());
-        return ::testing::AssertionFailure(::testing::Message(msg.string()));
+        fprintf(stderr, "assertRectEq: %s\n", msg.c_str());
+        return ::testing::AssertionFailure(::testing::Message(msg.c_str()));
     } else {
         return ::testing::AssertionSuccess();
     }
diff --git a/libs/gui/tests/SurfaceTextureFBO_test.cpp b/libs/gui/tests/SurfaceTextureFBO_test.cpp
index f34561f..ccd0e59 100644
--- a/libs/gui/tests/SurfaceTextureFBO_test.cpp
+++ b/libs/gui/tests/SurfaceTextureFBO_test.cpp
@@ -59,7 +59,7 @@
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
 
     for (int i = 0; i < 4; i++) {
-        SCOPED_TRACE(String8::format("frame %d", i).string());
+        SCOPED_TRACE(String8::format("frame %d", i).c_str());
 
         ASSERT_EQ(NO_ERROR, native_window_dequeue_buffer_and_wait(mANW.get(),
                 &anb));
diff --git a/libs/gui/tests/SurfaceTextureGL_test.cpp b/libs/gui/tests/SurfaceTextureGL_test.cpp
index e2b4f3d..f76c0be 100644
--- a/libs/gui/tests/SurfaceTextureGL_test.cpp
+++ b/libs/gui/tests/SurfaceTextureGL_test.cpp
@@ -147,8 +147,9 @@
 
     for (int i = 0; i < 5; i++) {
         const android_native_rect_t& crop(crops[i]);
-        SCOPED_TRACE(String8::format("rect{ l: %d t: %d r: %d b: %d }",
-                crop.left, crop.top, crop.right, crop.bottom).string());
+        SCOPED_TRACE(String8::format("rect{ l: %d t: %d r: %d b: %d }", crop.left, crop.top,
+                                     crop.right, crop.bottom)
+                             .c_str());
 
         ASSERT_EQ(NO_ERROR, native_window_set_crop(mANW.get(), &crop));
 
@@ -308,7 +309,7 @@
     mFW->waitForFrame();
 
     for (int i = 0; i < numFrames; i++) {
-        SCOPED_TRACE(String8::format("frame %d", i).string());
+        SCOPED_TRACE(String8::format("frame %d", i).c_str());
 
         // We must wait for each frame to come in because if we ever do an
         // updateTexImage call that doesn't consume a newly available buffer
diff --git a/libs/gui/tests/Surface_test.cpp b/libs/gui/tests/Surface_test.cpp
index 096a43c..4f4f1f5 100644
--- a/libs/gui/tests/Surface_test.cpp
+++ b/libs/gui/tests/Surface_test.cpp
@@ -413,7 +413,7 @@
     sp<ANativeWindow> window(surface);
     native_window_api_connect(window.get(), NATIVE_WINDOW_API_CPU);
 
-    EXPECT_STREQ("TestConsumer", surface->getConsumerName().string());
+    EXPECT_STREQ("TestConsumer", surface->getConsumerName().c_str());
 }
 
 TEST_F(SurfaceTest, GetWideColorSupport) {