tests: Remove some unused "using" declarations
diff --git a/tests/gtest/avifgridapitest.cc b/tests/gtest/avifgridapitest.cc
index 6bfe9c3..4d634c2 100644
--- a/tests/gtest/avifgridapitest.cc
+++ b/tests/gtest/avifgridapitest.cc
@@ -8,10 +8,6 @@
 #include "aviftest_helpers.h"
 #include "gtest/gtest.h"
 
-using testing::Combine;
-using testing::Values;
-using testing::ValuesIn;
-
 namespace libavif {
 namespace {
 
diff --git a/tests/gtest/avifrgbtoyuvtest.cc b/tests/gtest/avifrgbtoyuvtest.cc
index b66c852..a0254e8 100644
--- a/tests/gtest/avifrgbtoyuvtest.cc
+++ b/tests/gtest/avifrgbtoyuvtest.cc
@@ -14,7 +14,6 @@
 using ::testing::Combine;
 using ::testing::Range;
 using ::testing::Values;
-using ::testing::ValuesIn;
 
 namespace libavif {
 namespace {