diff --git a/openmc/region.py b/openmc/region.py
index eeafd28326..54797f5688 100644
--- a/openmc/region.py
+++ b/openmc/region.py
@@ -39,10 +39,8 @@ class Region(object):
     def __eq__(self, other):
         if not isinstance(other, type(self)):
             return False
-        elif str(self) != str(other):
-            return False
         else:
-            return True
+            return str(self) == str(other)
 
     def __ne__(self, other):
         return not self == other
@@ -463,7 +461,7 @@ class Union(Region, MutableSequence):
         if memo is None:
             memo = {}
 
-        clone = copy.deepcopy(self)
+        clone = deepcopy(self)
         clone[:] = [n.clone(memo) for n in self]
         return clone
 
@@ -584,6 +582,6 @@ class Complement(Region):
         if memo is None:
             memo = {}
 
-        clone = copy.deepcopy(self)
+        clone = deepcopy(self)
         clone.node = self.node.clone(memo)
         return clone
diff --git a/tests/unit_tests/test_region.py b/tests/unit_tests/test_region.py
new file mode 100644
index 0000000000..346ec7d95e
--- /dev/null
+++ b/tests/unit_tests/test_region.py
@@ -0,0 +1,134 @@
+import numpy as np
+import pytest
+import openmc
+
+
+@pytest.fixture
+def reset():
+    openmc.reset_auto_ids()
+
+
+def assert_unbounded(region):
+    ll, ur = region.bounding_box
+    assert ll == pytest.approx((-np.inf, -np.inf, -np.inf))
+    assert ur == pytest.approx((np.inf, np.inf, np.inf))
+
+
+def test_union(reset):
+    s1 = openmc.XPlane(surface_id=1, x0=5)
+    s2 = openmc.XPlane(surface_id=2, x0=-5)
+    region = +s1 | -s2
+    assert isinstance(region, openmc.Union)
+
+    # Check bounding box
+    assert_unbounded(region)
+
+    # __contains__
+    assert (6, 0, 0) in region
+    assert (-6, 0, 0) in region
+    assert (0, 0, 0) not in region
+
+    # string representation
+    assert str(region) == '(1 | -2)'
+
+    # Combining region with intersection
+    s3 = openmc.YPlane(surface_id=3)
+    reg2 = region & +s3
+    assert (6, 1, 0) in reg2
+    assert (6, -1, 0) not in reg2
+    assert str(reg2) == '((1 | -2) 3)'
+
+
+def test_intersection(reset):
+    s1 = openmc.XPlane(surface_id=1, x0=5)
+    s2 = openmc.XPlane(surface_id=2, x0=-5)
+    region = -s1 & +s2
+    assert isinstance(region, openmc.Intersection)
+
+    # Check bounding box
+    ll, ur = region.bounding_box
+    assert ll == pytest.approx((-5, -np.inf, -np.inf))
+    assert ur == pytest.approx((5, np.inf, np.inf))
+
+    # __contains__
+    assert (6, 0, 0) not in region
+    assert (-6, 0, 0) not in region
+    assert (0, 0, 0) in region
+
+    # string representation
+    assert str(region) == '(-1 2)'
+
+    # Combining region with union
+    s3 = openmc.YPlane(surface_id=3)
+    reg2 = region | +s3
+    assert (-6, 2, 0) in reg2
+    assert (-6, -2, 0) not in reg2
+    assert str(reg2) == '((-1 2) | 3)'
+
+
+def test_complement(reset):
+    zcyl = openmc.ZCylinder(surface_id=1, R=1.)
+    z0 = openmc.ZPlane(surface_id=2, z0=-5.)
+    z1 = openmc.ZPlane(surface_id=3, z0=5.)
+    outside = +zcyl | -z0 | +z1
+    inside = ~outside
+    outside_equiv = ~(-zcyl & +z0 & -z1)
+    inside_equiv = ~outside_equiv
+
+    # Check bounding box
+    for region in (inside, inside_equiv):
+        ll, ur = region.bounding_box
+        assert ll == pytest.approx((-1., -1., -5.))
+        assert ur == pytest.approx((1., 1., 5.))
+    assert_unbounded(outside)
+    assert_unbounded(outside_equiv)
+
+    # string represention
+    assert str(inside) == '~(1 | -2 | 3)'
+
+    # evaluate method
+    assert (0, 0, 0) in inside
+    assert (0, 0, 0) not in outside
+    assert (0, 0, 6) not in inside
+    assert (0, 0, 6) in outside
+
+
+def test_get_surfaces():
+    s1 = openmc.XPlane()
+    s2 = openmc.YPlane()
+    s3 = openmc.ZPlane()
+    region = (+s1 & -s2) | +s3
+
+    # Make sure get_surfaces() returns all surfaces
+    surfs = set(region.get_surfaces().values())
+    assert not (surfs ^ {s1, s2, s3})
+
+    inverse = ~region
+    surfs = set(inverse.get_surfaces().values())
+    assert not (surfs ^ {s1, s2, s3})
+
+
+def test_extend_clone():
+    s1 = openmc.XPlane()
+    s2 = openmc.YPlane()
+    s3 = openmc.ZPlane()
+    s4 = openmc.ZCylinder()
+
+    # extend intersection
+    r1 = +s1 & -s2
+    r1 &= +s3 & -s4
+    assert r1[:] == [+s1, -s2, +s3, -s4]
+
+    # extend union
+    r2 = +s1 | -s2
+    r2 |= +s3 | -s4
+    assert r2[:] == [+s1, -s2, +s3, -s4]
+
+    # clone methods
+    r3 = r1.clone()
+    assert len(r3) == len(r1)
+    r4 = r2.clone()
+    assert len(r4) == len(r2)
+
+    r5 = ~r1
+    r6 = r5.clone()
diff --git a/tests/unit_tests/test_surface.py b/tests/unit_tests/test_surface.py
index ded6cf1f2a..3db84cc053 100644
--- a/tests/unit_tests/test_surface.py
+++ b/tests/unit_tests/test_surface.py
@@ -80,6 +80,7 @@ def test_yplane():
     # evaluate method
     assert s.evaluate((0., 0., 0.)) == pytest.approx(-3.)
 
+
 def test_zplane():
     s = openmc.ZPlane(z0=3.)
     assert s.z0 == 3.