diff --git a/pytest.ini b/pytest.ini
new file mode 100644
index 0000000..51d76c8
--- /dev/null
+++ b/pytest.ini
@@ -0,0 +1,6 @@
+[pytest]
+markers =
+    slow: marks tests as slow (deselect with '-m "not slow"')
+
+pythonpath = .
+testpaths = tests
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/chimp/__init__.py b/tests/chimp/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/cmaps/__init__.py b/tests/cmaps/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/conftest.py b/tests/conftest.py
index 1327c7f..f52f291 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -92,4 +92,13 @@ def mix_file(tmpdir):
     ftag = "test"
     file_path = fdir.join("test.mix.h5")
     file_path = write_mix_h5(file_path)
-    return file_path
\ No newline at end of file
+    return file_path
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--runslow", action="store_true", default=False, help="run tests marked as slow"
+    )
+
+def pytest_runtest_setup(item):
+    if "slow" in item.keywords and not item.config.getoption("--runslow"):
+        pytest.skip("need --runslow option to run")
\ No newline at end of file
diff --git a/tests/gamera/__init__.py b/tests/gamera/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/rcm/__init__.py b/tests/rcm/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/remix/__init__.py b/tests/remix/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/satcomp/__init__.py b/tests/satcomp/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/satcomp/test_satcomp_cdasws.py b/tests/satcomp/test_satcomp_cdasws.py
index 4f85e67..95b9666 100644
--- a/tests/satcomp/test_satcomp_cdasws.py
+++ b/tests/satcomp/test_satcomp_cdasws.py
@@ -21,7 +21,7 @@ def test_emphem(key):
     assert 'CoordSys' in scIdDict[key]['Ephem'], \
         '{} lacks Ephem CoordSys key'.format(key)
 
-
+@pytest.mark.slow
 @pytest.mark.parametrize("key",[key for key in scutils.getScIds().keys()])
 def test_pullVar(key):