diff --git a/src/wagtail_personalisation/adapters.py b/src/wagtail_personalisation/adapters.py
index 5120472..8511627 100644
--- a/src/wagtail_personalisation/adapters.py
+++ b/src/wagtail_personalisation/adapters.py
@@ -78,6 +78,7 @@ class SessionSegmentsAdapter(BaseSegmentsAdapter):
     def __init__(self, request):
         super(SessionSegmentsAdapter, self).__init__(request)
         self.request.session.setdefault('segments', [])
+        self._segment_cache = None
 
     def get_segments(self):
         """Return the persistent segments stored in the request session.
@@ -86,6 +87,9 @@ class SessionSegmentsAdapter(BaseSegmentsAdapter):
         :rtype: list of wagtail_personalisation.models.Segment or empty list
 
         """
+        if self._segment_cache is not None:
+            return self._segment_cache
+
         raw_segments = self.request.session['segments']
         segment_ids = [segment['id'] for segment in raw_segments]
 
@@ -95,7 +99,9 @@ class SessionSegmentsAdapter(BaseSegmentsAdapter):
             .filter(persistent=True)
             .in_bulk(segment_ids))
 
-        return [segments[pk] for pk in segment_ids if pk in segments]
+        retval = [segments[pk] for pk in segment_ids if pk in segments]
+        self._segment_cache = retval
+        return retval
 
     def set_segments(self, segments):
         """Set the currently active segments
@@ -104,6 +110,7 @@ class SessionSegmentsAdapter(BaseSegmentsAdapter):
         :type segments: list of wagtail_personalisation.models.Segment
 
         """
+        cache_segments = []
         serialized_segments = []
         segment_ids = set()
         for segment in segments:
@@ -111,10 +118,12 @@ class SessionSegmentsAdapter(BaseSegmentsAdapter):
             if serialized['id'] in segment_ids:
                 continue
 
+            cache_segments.append(segment)
             serialized_segments.append(serialized)
             segment_ids.add(segment.pk)
 
         self.request.session['segments'] = serialized_segments
+        self._segment_cache = cache_segments
 
     def get_segment_by_id(self, segment_id):
         """Find and return a single segment from the request session.
@@ -125,11 +134,8 @@ class SessionSegmentsAdapter(BaseSegmentsAdapter):
         :rtype: wagtail_personalisation.models.Segment or None
 
         """
-        try:
-            return next(item for item in self.request.session['segments']
-                        if item['id'] == segment_id)
-        except StopIteration:
-            return None
+        segments = self.get_segments()
+        return next((s for s in segments if s.pk == segment_id), None)
 
     def add_page_visit(self, page):
         """Mark the page as visited by the user"""
diff --git a/tests/conftest.py b/tests/conftest.py
index 0537186..8942e2e 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -2,8 +2,6 @@ from __future__ import absolute_import, unicode_literals
 
 import pytest
 from wagtail.wagtailcore.models import Page, Site
-from wagtail_factories import SiteFactory
-from tests.factories.page import PageFactory
 
 pytest_plugins = [
     'tests.fixtures'
@@ -16,4 +14,3 @@ def django_db_setup(django_db_setup, django_db_blocker):
         # Remove some initial data that is brought by the sandbox module
         Site.objects.all().delete()
         Page.objects.all().exclude(depth=1).delete()
-
diff --git a/tests/factories/segment.py b/tests/factories/segment.py
index 5ea0b6c..f92f579 100644
--- a/tests/factories/segment.py
+++ b/tests/factories/segment.py
@@ -7,7 +7,7 @@ from wagtail_personalisation import models
 
 class SegmentFactory(factory.DjangoModelFactory):
     name = 'TestSegment'
-    status = 'enabled'
+    status = models.Segment.STATUS_ENABLED
 
     class Meta:
         model = models.Segment
diff --git a/tests/fixtures.py b/tests/fixtures.py
index d023261..0e3e437 100644
--- a/tests/fixtures.py
+++ b/tests/fixtures.py
@@ -1,5 +1,9 @@
 import pytest
 
+from django.contrib.auth.models import AnonymousUser
+from django.contrib.messages.storage.fallback import FallbackStorage
+from django.contrib.sessions.backends.db import SessionStore
+from django.test.client import RequestFactory as BaseRequestFactory
 from tests.factories.page import PageFactory
 from tests.factories.segment import SegmentFactory
 from tests.factories.site import SiteFactory
@@ -18,3 +22,19 @@ def segmented_page(site):
     page = PageFactory(parent=site.root_page)
     segment = SegmentFactory()
     return page.copy_for_segment(segment)
+
+
+@pytest.fixture()
+def rf():
+    """RequestFactory instance"""
+    return RequestFactory()
+
+
+class RequestFactory(BaseRequestFactory):
+
+    def request(self, user=None, **request):
+        request = super(RequestFactory, self).request(**request)
+        request.user = AnonymousUser()
+        request.session = SessionStore()
+        request._messages = FallbackStorage(request)
+        return request
diff --git a/tests/unit/test_adapter_session.py b/tests/unit/test_adapter_session.py
new file mode 100644
index 0000000..75f4bcc
--- /dev/null
+++ b/tests/unit/test_adapter_session.py
@@ -0,0 +1,35 @@
+import pytest
+
+from wagtail_personalisation import adapters
+from tests.factories.segment import SegmentFactory
+
+
+@pytest.mark.django_db
+def test_get_segments(rf, monkeypatch):
+    request = rf.get('/')
+
+    adapter = adapters.SessionSegmentsAdapter(request)
+
+    segment_1 = SegmentFactory(name='segment-1', persistent=True)
+    segment_2 = SegmentFactory(name='segment-2', persistent=True)
+
+    adapter.set_segments([segment_1, segment_2])
+    assert len(request.session['segments']) == 2
+
+    segments = adapter.get_segments()
+    assert segments == [segment_1, segment_2]
+
+
+@pytest.mark.django_db
+def test_get_segment_by_id(rf, monkeypatch):
+    request = rf.get('/')
+
+    adapter = adapters.SessionSegmentsAdapter(request)
+
+    segment_1 = SegmentFactory(name='segment-1', persistent=True)
+    segment_2 = SegmentFactory(name='segment-2', persistent=True)
+
+    adapter.set_segments([segment_1, segment_2])
+
+    segment_x = adapter.get_segment_by_id(segment_2.pk)
+    assert segment_x == segment_2