diff --git a/tests/test_pixel_ranges.py b/tests/test_pixel_ranges.py
index 08855b8..f661395 100644
--- a/tests/test_pixel_ranges.py
+++ b/tests/test_pixel_ranges.py
@@ -10,6 +10,8 @@ def test_update_values_pixel_ranges(self):
         nside_coverage = 32
         nside_map = 256
 
+        orig_threshold = healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD
+
         # Monkey-patch PIXEL_RANGE_THRESHOLD for testing.
         healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = 0
 
@@ -71,10 +73,14 @@ def _none_checker(_m1, _m2, start, stop, cov_mask):
             # None value: narrow range, no overlap.
             _none_checker(m1, m2, 200000, 200010, cov_mask)
 
+        healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = orig_threshold
+
     def test_update_values_pixel_ranges_empty(self):
         nside_coverage = 32
         nside_map = 256
 
+        orig_threshold = healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD
+
         # Monkey-patch PIXEL_RANGE_THRESHOLD for testing.
         healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = 0
 
@@ -86,10 +92,14 @@ def test_update_values_pixel_ranges_empty(self):
 
         self.assertEqual(m1.n_valid, 0)
 
+        healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = orig_threshold
+
     def test_update_values_pixel_ranges_or(self):
         nside_coverage = 32
         nside_map = 256
 
+        orig_threshold = healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD
+
         # Monkey-patch PIXEL_RANGE_THRESHOLD for testing.
         healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = 0
 
@@ -128,10 +138,14 @@ def test_update_values_pixel_ranges_or(self):
             testing.assert_array_equal(m1.valid_pixels, m2.valid_pixels)
             testing.assert_array_equal(m1[m1.valid_pixels], m2[m2.valid_pixels])
 
+        healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = orig_threshold
+
     def test_update_values_pixel_ranges_and(self):
         nside_coverage = 32
         nside_map = 256
 
+        orig_threshold = healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD
+
         # Monkey-patch PIXEL_RANGE_THRESHOLD for testing.
         healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = 0
 
@@ -170,10 +184,14 @@ def test_update_values_pixel_ranges_and(self):
             testing.assert_array_equal(m1.valid_pixels, m2.valid_pixels)
             testing.assert_array_equal(m1[m1.valid_pixels], m2[m2.valid_pixels])
 
+        healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = orig_threshold
+
     def test_update_values_pixel_ranges_add(self):
         nside_coverage = 32
         nside_map = 256
 
+        orig_threshold = healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD
+
         # Monkey-patch PIXEL_RANGE_THRESHOLD for testing.
         healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = 0
 
@@ -206,10 +224,14 @@ def test_update_values_pixel_ranges_add(self):
             testing.assert_array_equal(m1.valid_pixels, m2.valid_pixels)
             testing.assert_array_equal(m1[m1.valid_pixels], m2[m2.valid_pixels])
 
+        healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = orig_threshold
+
     def test_set_bits_pix_pixel_ranges(self):
         nside_coverage = 32
         nside_map = 256
 
+        orig_threshold = healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD
+
         # Monkey-patch PIXEL_RANGE_THRESHOLD for testing.
         healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = 0
 
@@ -232,6 +254,8 @@ def test_set_bits_pix_pixel_ranges(self):
         testing.assert_array_equal(m1.valid_pixels, m2.valid_pixels)
         testing.assert_array_equal(m1[m1.valid_pixels], m2[m2.valid_pixels])
 
+        healsparse.healSparseMap.PIXEL_RANGE_THRESHOLD = orig_threshold
+
 
 if __name__ == '__main__':
     unittest.main()