diff --git a/src/drc/unit_tests/drcBasicTests.cc b/src/drc/unit_tests/drcBasicTests.cc
index ac6c9a550..5e0626a0c 100644
--- a/src/drc/unit_tests/drcBasicTests.cc
+++ b/src/drc/unit_tests/drcBasicTests.cc
@@ -30,7 +30,7 @@ TEST(1)
   std::string input = tl::testsrc ();
   input += "/testdata/drc/drctest.gds";
   std::string au = tl::testsrc ();
-  au += "/testdata/drc/drcBasicTests_au.gds";
+  au += "/testdata/drc/drcBasicTests_au.oas";
 
   std::string output = this->tmp_file ("tmp.gds");
 
diff --git a/src/drc/unit_tests/drcSimpleTests.cc b/src/drc/unit_tests/drcSimpleTests.cc
index 06c4fd22c..d038e18f0 100644
--- a/src/drc/unit_tests/drcSimpleTests.cc
+++ b/src/drc/unit_tests/drcSimpleTests.cc
@@ -31,7 +31,7 @@ TEST(1)
   rs += "/testdata/drc/drcSimpleTests_1.drc";
 
   std::string au = tl::testsrc ();
-  au += "/testdata/drc/drcSimpleTests_au1.gds";
+  au += "/testdata/drc/drcSimpleTests_au1.oas";
 
   std::string output = this->tmp_file ("tmp.gds");
 
@@ -71,7 +71,7 @@ TEST(2)
   input += "/testdata/drc/drctest.gds";
 
   std::string au = tl::testsrc ();
-  au += "/testdata/drc/drcSimpleTests_au2.gds";
+  au += "/testdata/drc/drcSimpleTests_au2.oas";
 
   std::string output = this->tmp_file ("tmp.gds");
 
@@ -111,7 +111,7 @@ TEST(3)
   input += "/testdata/drc/drctest.gds";
 
   std::string au = tl::testsrc ();
-  au += "/testdata/drc/drcSimpleTests_au3.gds";
+  au += "/testdata/drc/drcSimpleTests_au3.oas";
 
   std::string output = this->tmp_file ("tmp.gds");
 
diff --git a/src/drc/unit_tests/drcSuiteTests.cc b/src/drc/unit_tests/drcSuiteTests.cc
index 535afbaa2..c977af56e 100644
--- a/src/drc/unit_tests/drcSuiteTests.cc
+++ b/src/drc/unit_tests/drcSuiteTests.cc
@@ -36,7 +36,7 @@ void runtest (tl::TestBase *_this, int mode)
   std::string au = tl::testsrc ();
   au += "/testdata/drc/drcSuiteTests_au";
   au += tl::to_string (mode);
-  au += ".gds";
+  au += ".oas";
 
   std::string output = _this->tmp_file ("tmp.gds");
 
diff --git a/testdata/drc/drcBasicTests_au.gds b/testdata/drc/drcBasicTests_au.oas
similarity index 100%
rename from testdata/drc/drcBasicTests_au.gds
rename to testdata/drc/drcBasicTests_au.oas
diff --git a/testdata/drc/drcSimpleTests_au1.gds b/testdata/drc/drcSimpleTests_au1.oas
similarity index 100%
rename from testdata/drc/drcSimpleTests_au1.gds
rename to testdata/drc/drcSimpleTests_au1.oas
diff --git a/testdata/drc/drcSimpleTests_au2.gds b/testdata/drc/drcSimpleTests_au2.oas
similarity index 100%
rename from testdata/drc/drcSimpleTests_au2.gds
rename to testdata/drc/drcSimpleTests_au2.oas
diff --git a/testdata/drc/drcSimpleTests_au3.gds b/testdata/drc/drcSimpleTests_au3.oas
similarity index 100%
rename from testdata/drc/drcSimpleTests_au3.gds
rename to testdata/drc/drcSimpleTests_au3.oas
diff --git a/testdata/drc/drcSuiteTests_au1.gds b/testdata/drc/drcSuiteTests_au1.oas
similarity index 100%
rename from testdata/drc/drcSuiteTests_au1.gds
rename to testdata/drc/drcSuiteTests_au1.oas
diff --git a/testdata/drc/drcSuiteTests_au2.gds b/testdata/drc/drcSuiteTests_au2.oas
similarity index 100%
rename from testdata/drc/drcSuiteTests_au2.gds
rename to testdata/drc/drcSuiteTests_au2.oas
diff --git a/testdata/drc/drcSuiteTests_au3.gds b/testdata/drc/drcSuiteTests_au3.oas
similarity index 100%
rename from testdata/drc/drcSuiteTests_au3.gds
rename to testdata/drc/drcSuiteTests_au3.oas
diff --git a/testdata/drc/drcSuiteTests_au4.gds b/testdata/drc/drcSuiteTests_au4.oas
similarity index 100%
rename from testdata/drc/drcSuiteTests_au4.gds
rename to testdata/drc/drcSuiteTests_au4.oas