diff --git a/mitmproxy/addons/intercept.py b/mitmproxy/addons/intercept.py
index 20599e19f..14ef7410a 100644
--- a/mitmproxy/addons/intercept.py
+++ b/mitmproxy/addons/intercept.py
@@ -1,4 +1,4 @@
-import ctx
+from mitmproxy import ctx
 from mitmproxy import flowfilter
 from mitmproxy import exceptions
 
@@ -11,8 +11,8 @@ class Intercept:
         if "intercept" in updated:
             if not opts.intercept:
                 self.filt = None
-            filt = flowfilter.parse(opts.intercept)
-            if not filt:
+            self.filt = flowfilter.parse(opts.intercept)
+            if not self.filt:
                 raise exceptions.OptionsError(
                     "Invalid interception filter: %s" % opts.intercept
                 )
diff --git a/mitmproxy/test/taddons.py b/mitmproxy/test/taddons.py
new file mode 100644
index 000000000..a22fd5e24
--- /dev/null
+++ b/mitmproxy/test/taddons.py
@@ -0,0 +1,37 @@
+import mitmproxy.master
+import mitmproxy.options
+from mitmproxy import proxy
+
+
+class context:
+    """
+        A helper context for testing addons. Its most important function is to
+        set up the ctx module so handlers can be called just like they would be
+        when running from within mitmproxy.
+    """
+    def __init__(self, master = None, options = None):
+        self.options = options or mitmproxy.options.Options()
+        self.master = master or mitmproxy.master.Master(
+            options, proxy.DummyServer(options)
+        )
+        self.wrapped = None
+
+    def __enter__(self):
+        self.wrapped = self.master.handlecontext()
+        self.wrapped.__enter__()
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.wrapped.__exit__(exc_type, exc_value, traceback)
+        self.wrapped = None
+        return False
+
+    def configure(self, addon, **kwargs):
+        """
+            A helper for testing configure methods. Modifies the registered
+            Options object with the given keyword arguments, then calls the
+            configure method on the addon with the updated value.
+        """
+        for k, v in kwargs.items():
+            setattr(self.options, k, v)
+        addon.configure(self.options, kwargs.keys())
diff --git a/test/mitmproxy/addons/test_intercept.py b/test/mitmproxy/addons/test_intercept.py
index e69de29bb..19828a629 100644
--- a/test/mitmproxy/addons/test_intercept.py
+++ b/test/mitmproxy/addons/test_intercept.py
@@ -0,0 +1,25 @@
+from mitmproxy.addons import intercept
+from mitmproxy import options
+from mitmproxy import exceptions
+from mitmproxy.test import taddons
+from mitmproxy.test import tutils
+
+
+class Options(options.Options):
+    def __init__(self, *, intercept=None, **kwargs):
+        self.intercept = intercept
+        super().__init__(**kwargs)
+
+
+def test_simple():
+    r = intercept.Intercept()
+    with taddons.context(options=Options()) as tctx:
+        assert not r.filt
+        tctx.configure(r, intercept="~q")
+        assert r.filt
+        tutils.raises(
+            exceptions.OptionsError,
+            tctx.configure,
+            r,
+            intercept="~~"
+        )
diff --git a/test/mitmproxy/mastertest.py b/test/mitmproxy/mastertest.py
index cdfb5ad52..0672add90 100644
--- a/test/mitmproxy/mastertest.py
+++ b/test/mitmproxy/mastertest.py
@@ -10,10 +10,6 @@ from mitmproxy import http
 from mitmproxy import options
 
 
-class TestMaster:
-    pass
-
-
 class MasterTest:
 
     def cycle(self, master, content):