diff --git a/testing/code/test_code.py b/testing/_code/test_code.py
similarity index 100%
rename from testing/code/test_code.py
rename to testing/_code/test_code.py
diff --git a/testing/code/test_excinfo.py b/testing/_code/test_excinfo.py
similarity index 100%
rename from testing/code/test_excinfo.py
rename to testing/_code/test_excinfo.py
diff --git a/testing/code/test_source.py b/testing/_code/test_source.py
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rename from testing/code/test_source.py
rename to testing/_code/test_source.py
diff --git a/testing/io/test_saferepr.py b/testing/_io/test_saferepr.py
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rename from testing/io/test_saferepr.py
rename to testing/_io/test_saferepr.py
diff --git a/testing/io/test_terminalwriter.py b/testing/_io/test_terminalwriter.py
similarity index 100%
rename from testing/io/test_terminalwriter.py
rename to testing/_io/test_terminalwriter.py