diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,16 @@
 # Changelog for hasklepias
 
+## 0.16.0
+
+* Adds a basic framework for `Feature` definition templates. Initially, this includes two templates for enrollment related features:
+  * `defIsEnrolled` is a definition that maps an `Index` and a container of `Event`s to a `Status` (i.e. `Include` or `Exclude`). This template takes no arguments.
+  * `defContinuousEnrollment` is a definition that maps an `Index`, a container of `Event`s, and a `Status` to a `Status`. This template takes two arguments: a function that creates the interval from the index during which enrollment is assessed and an allowable gap between any enrollment intervals. The input `Status` is used so that continuous enrollment may depend on other statuses. For example, you may want to have continuous enrollment depend on being enrolled.
+* Adds a framework for testing the templates. E.g. templates can be tested using `cabal test templates`.
+* Updates the `ExampleCohort1` to use the `defIsEnrolled` and `defContinuousEnrollment` templates.
+* Makes the `Index i a` type an instance of `Intervallic`, so you can use methods like `begin`, `end`, and interval algebra functions directly on an `Index` without having to unpack the interval first.
+* Adds stripped down `Enrollment` Domain. This does type is not faithful to the EDM, as it does not include the event data model's plan fact.
+* Adds the `isEnrollment` predicate function for identifying `Domain`s that are Enrollment. This can be used with `filterByDomain` to filter a container of `Event`s to those that are enrollment events.
+
 ## 0.15.2
 
 * Updates `viewBirthYears` utility to filter a list of events to those with `BirthYear` demographic facts. In this way, one doesn't need to prefilter the input list by, e.g., a concept.
diff --git a/examples/ExampleCohort1.hs b/examples/ExampleCohort1.hs
--- a/examples/ExampleCohort1.hs
+++ b/examples/ExampleCohort1.hs
@@ -40,22 +40,22 @@
 
 -- | Creates a baseline interval from index
 baselineInterval :: Index Interval Day -> Interval Day
-baselineInterval index = lookback baselineLookback (getIndex index)
+baselineInterval = lookback baselineLookback
 
 -- | Shifts an interval by a calendar amount
-shiftIntervalDay :: CalendarDiffDays -> Interval Day -> Interval Day
+shiftIntervalDay :: (Intervallic i Day) => CalendarDiffDays -> i Day -> Interval Day
 shiftIntervalDay cd i = beginerval (duration i) (addGregorianDurationClip cd (begin i))
 
 -- | Creates an interval *beginning the same day as the index* and 
 --   ending 'followupDuration' days later.
 followupInterval :: Index Interval Day -> Interval Day
-followupInterval index = beginerval (diff bi (end $ shiftIntervalDay followupDuration i)) bi
-    where i = getIndex index
-          bi = begin i
+followupInterval index = 
+    beginerval (diff (begin index) (end $ shiftIntervalDay followupDuration index)) (begin index)
 
+
 -- | A predicate function that determines if some interval is before index
 beforeIndex :: Intervallic i Day => Index Interval Day -> i Day -> Bool
-beforeIndex index = before (getIndex index)
+beforeIndex = before
 
 -- | Creates a filter for events to those that 'concur' with the baseline interval.
 getBaselineConcur ::  Index Interval Day -> Events Day -> [Event Day]
@@ -126,21 +126,6 @@
 featureIndex :: Index Interval Day -> Feature "calendarIndex"  (Index Interval Day)
 featureIndex = pure
 
---- | Gets all enrollment intervals and combines them any place they concur. 
---    Returns an error if there are no enrollment intervals.
-enrollmentIntervals :: Definition
-  (  Feature "allEvents" (Events Day)
-  -> Feature "enrollmentIntervals" [Interval Day])
-enrollmentIntervals =
-  defineA
-      (\events ->
-              events
-          |> makeConceptsFilter ["enrollment"]
-          |> combineIntervals
-          |> (\x -> if null x then makeFeature $ missingBecause $ Other "no enrollment intervals"
-                    else pure x)
-      )
-
 -- | The subject's age at time of index. Returns an error if there no birth year
 --   records.
 age :: Definition
@@ -155,7 +140,7 @@
       |> viewBirthYears
       |> headMay
       |> fmap (\y  -> fromGregorian y 1 7)  -- Use July 1 YEAR as birthdate
-      |> fmap (\bday -> computeAgeAt bday (begin $ getIndex index) )
+      |> fmap (\bday -> computeAgeAt bday (begin index) )
       |> \case
             Nothing -> makeFeature $ featureDataL $ Other "No numeric birth year found"
             Just age -> pure age
@@ -203,15 +188,9 @@
 -- | Include the subject if she has an enrollment interval concurring with index.
 critEnrolled :: Definition
   (   Feature "calendarIndex" (Index Interval Day)
-   -> Feature "enrollmentIntervals" [Interval Day]
+   -> Feature "allEvents" [Event Day]
    -> Feature "isEnrolled" Status )
-critEnrolled =
-  define
-      (\index enrollmentIntervals ->
-        enrollmentIntervals
-        |> any (concur $ getIndex index)
-        |> includeIf
-      )
+critEnrolled = defIsEnrolled
 
 -- | Include the subject if both:
 --     * she is enrolled on index ('critEnrolled')
@@ -219,16 +198,10 @@
 --       are less than 30 days
 critEnrolled455 :: Definition
   (   Feature "calendarIndex" (Index Interval Day)
-   -> Feature "enrollmentIntervals" [Interval Day]
+   -> Feature "allEvents" [Event Day]
    -> Feature "isEnrolled" Status
    -> Feature "isContinuousEnrolled" Status )
-critEnrolled455 =
-  define
-      (\index enrollIntrvls isEnrolled ->
-        case isEnrolled of
-          Exclude -> Exclude
-          Include -> includeIf ( allGapsWithinLessThanDuration 30 (baselineInterval index) enrollIntrvls)
-      )
+critEnrolled455 = defContinuousEnrollment baselineInterval 30
 
 -- | Exclude if the subject is dead before the time of index.
 critDead :: Definition
@@ -298,8 +271,6 @@
     [Covariate]
     ["baseline"]
 
--- instance HasAttributes "" (*)
-
 {-------------------------------------------------------------------------------
   Cohort Specifications and evaluation
 -------------------------------------------------------------------------------}
@@ -315,11 +286,10 @@
     , criterion crit5 ]
   where crit1   = eval critFemale featEvs
         crit2   = eval critOver50 agefeat
-        crit3   = eval critEnrolled (featInd, enrll)
-        crit4   = eval critEnrolled455 (featInd, enrll, crit3)
+        crit3   = eval critEnrolled (featInd, featEvs)
+        crit4   = eval critEnrolled455 (featInd, featEvs, crit3)
         crit5   = eval critDead (featInd, dead)
         agefeat = eval age (featInd, featEvs)
-        enrll   = eval enrollmentIntervals featEvs
         dead    = eval deathDay featEvs
         featInd = featureIndex index
         featEvs = featureEvents events
@@ -360,9 +330,9 @@
 testData1 = sort
     [ m 2010 1 1 1   ["is_female"] (Demographics (DemographicsFacts (DemographicsInfo Gender  (Just "Female")) ))
     , m 2010 1 1 1   ["is_birth_year"] (Demographics (DemographicsFacts (DemographicsInfo BirthYear (Just "1960")) ))
-    , m 2016 1 1 699 ["enrollment"] ( UnimplementedDomain ())
-    , m 2018 1 1 30  ["enrollment"] ( UnimplementedDomain ())
-    , m 2018 2 1 30  ["enrollment"] ( UnimplementedDomain ())
+    , m 2016 1 1 699 ["enrollment"] (Enrollment EnrollmentFacts)
+    , m 2018 1 1 30  ["enrollment"] (Enrollment EnrollmentFacts)
+    , m 2018 2 1 30  ["enrollment"] (Enrollment EnrollmentFacts)
     , m 2017 6 5 1   ["is_diabetes_inpatient"] (UnimplementedDomain ())
     , m 2017 8 1 91  ["is_ppi"] (UnimplementedDomain ())
     ]
@@ -374,9 +344,9 @@
 testData2 = sort
     [ m 2010 1 1 1   ["is_female"] (Demographics (DemographicsFacts (DemographicsInfo Gender  (Just "Female")) ))
     , m 2010 1 1 1   ["is_birth_year"] (Demographics (DemographicsFacts (DemographicsInfo BirthYear (Just "1980")) ))
-    , m 2016 1 1 730 ["enrollment"] (UnimplementedDomain ())
-    , m 2018 1 1 30  ["enrollment"] (UnimplementedDomain ())
-    , m 2018 2 1 30  ["enrollment"] (UnimplementedDomain ())
+    , m 2016 1 1 730 ["enrollment"] (Enrollment EnrollmentFacts)
+    , m 2018 1 1 30  ["enrollment"] (Enrollment EnrollmentFacts)
+    , m 2018 2 1 30  ["enrollment"] (Enrollment EnrollmentFacts)
     ]
 
 testSubject2 :: Subject (Events Day)
diff --git a/examples/ExampleFeatures4.hs b/examples/ExampleFeatures4.hs
--- a/examples/ExampleFeatures4.hs
+++ b/examples/ExampleFeatures4.hs
@@ -168,7 +168,7 @@
                         , IntervalSizeable a b) => 
     b -> Index i a -> Interval a
 makeFollowupInterval dur index =  
-  beginerval dur (add washoutDuration (begin $ getIndex index))
+  beginerval dur (add washoutDuration (begin index))
 
 -- | Creates an interval *starting 7 days after the index* and 
 --   ending 'followupDuration' days later.
diff --git a/hasklepias.cabal b/hasklepias.cabal
--- a/hasklepias.cabal
+++ b/hasklepias.cabal
@@ -1,6 +1,6 @@
 cabal-version:  2.2
 name:           hasklepias
-version:        0.15.2
+version:        0.16.0
 description:    Please see the README on GitHub at <https://github.com/novisci/asclepias#readme>
 homepage:       https://github.com/novisci/asclepias/#readme
 bug-reports:    https://github.com/novisci/asclepias/issues
@@ -30,6 +30,7 @@
       EventData.Context.Arbitrary
       EventData.Context.Domain
       EventData.Context.Domain.Demographics
+      EventData.Context.Domain.Enrollment
       Features
       Features.Attributes
       Features.Compose
@@ -48,6 +49,11 @@
       Hasklepias.Misc
       Hasklepias.Reexports
       Hasklepias.ReexportsUnsafe
+      Hasklepias.Templates
+      Hasklepias.Templates.Features
+      Hasklepias.Templates.Tests
+      Hasklepias.Templates.TestUtilities
+      Hasklepias.Templates.Features.Enrollment
       Stype
       Stype.Aeson
       Stype.Numeric
@@ -128,6 +134,19 @@
     , unordered-containers >=0.2.10
     , vector >=0.12
     , QuickCheck
+  default-language: Haskell2010
+
+test-suite templates
+  type: exitcode-stdio-1.0
+  main-is: Main.hs
+  hs-source-dirs:
+      template-test
+  build-depends:
+      hasklepias
+    , base >=4.14 && <4.15
+    , tasty  == 1.4.1
+    , tasty-hunit == 0.10.0.3
+    , tasty-hspec == 1.2
   default-language: Haskell2010
 
 test-suite examples
diff --git a/src/Cohort/Index.hs b/src/Cohort/Index.hs
--- a/src/Cohort/Index.hs
+++ b/src/Cohort/Index.hs
@@ -9,19 +9,20 @@
 {-# OPTIONS_HADDOCK hide #-}
 {-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 -- {-# LANGUAGE Safe #-}
 
 module Cohort.Index(
-    Index
+    Index(..)
   , makeIndex
-  , getIndex
 ) where
 
 import GHC.Show                    ( Show )
-import GHC.Generics
+import GHC.Generics                ( Generic )
 import Data.Eq                     ( Eq )
-import IntervalAlgebra             ( Intervallic )
-import Data.Aeson
+import IntervalAlgebra             ( Intervallic(..) )
+import Data.Aeson                  ( ToJSON )
 
 {-|
 An @Index@ is a wrapper for an @Intervallic@ used to indicate that a particular
@@ -35,5 +36,9 @@
 -- | Creates a new @'Index'@.
 makeIndex :: Intervallic i a => i a -> Index i a
 makeIndex = MkIndex
+
+instance (Intervallic i a) => Intervallic (Index i) a where
+  getInterval (MkIndex x) = getInterval x
+  setInterval (MkIndex x) y = MkIndex (setInterval x y)
 
 instance (Intervallic i a, ToJSON (i a)) => ToJSON (Index i a) 
diff --git a/src/EventData/Context/Domain.hs b/src/EventData/Context/Domain.hs
--- a/src/EventData/Context/Domain.hs
+++ b/src/EventData/Context/Domain.hs
@@ -17,6 +17,8 @@
     Domain(..)
     , _Demographics
     , module EventData.Context.Domain.Demographics
+    , _Enrollment
+    , module EventData.Context.Domain.Enrollment
 ) where
 
 import Control.Lens                             ( makePrisms )
@@ -26,10 +28,12 @@
 import GHC.Show                                 ( Show )
 
 import EventData.Context.Domain.Demographics
+import EventData.Context.Domain.Enrollment
 
 -- | Defines the available domains.
 data Domain =
       Demographics DemographicsFacts
+    | Enrollment EnrollmentFacts
     | UnimplementedDomain ()
     deriving ( Eq, Show, Generic )
 
diff --git a/src/EventData/Context/Domain/Enrollment.hs b/src/EventData/Context/Domain/Enrollment.hs
new file mode 100644
--- /dev/null
+++ b/src/EventData/Context/Domain/Enrollment.hs
@@ -0,0 +1,39 @@
+{-|
+Module      : Event Data Model facts 
+Description : Defines the Context type and its component types, constructors, 
+              and class instances
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+-}
+{-# OPTIONS_HADDOCK hide #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE TemplateHaskell #-}
+
+module EventData.Context.Domain.Enrollment(
+  EnrollmentFacts(..)
+) where
+
+import Control.Lens             ( makeLenses )
+import Data.Aeson               ( FromJSON(..)
+                                , genericParseJSON
+                                , defaultOptions
+                                , fieldLabelModifier )
+import Data.List                ( drop )
+import Data.Eq                  ( Eq )
+import GHC.Generics             ( Generic )
+import GHC.Show                 ( Show )
+
+
+-- | An enrollment fact
+data EnrollmentFacts = EnrollmentFacts { 
+  -- TODO add plan fact
+  } 
+  deriving( Eq, Show, Generic )
+
+makeLenses ''EnrollmentFacts
+
+instance FromJSON EnrollmentFacts where
+  parseJSON = genericParseJSON defaultOptions{fieldLabelModifier = drop 1}
diff --git a/src/Hasklepias.hs b/src/Hasklepias.hs
--- a/src/Hasklepias.hs
+++ b/src/Hasklepias.hs
@@ -26,6 +26,9 @@
     , module Hasklepias.FeatureEvents
     , module Hasklepias.Misc
     
+    -- ** Feature definition templates
+    , module Hasklepias.Templates
+    
     -- * Specifying and building cohorts
     , module Cohort
 
@@ -55,5 +58,6 @@
 import Hasklepias.Reexports
 import Hasklepias.ReexportsUnsafe
 import Hasklepias.MakeApp
+import Hasklepias.Templates
 
 import Stype
diff --git a/src/Hasklepias/FeatureEvents.hs b/src/Hasklepias/FeatureEvents.hs
--- a/src/Hasklepias/FeatureEvents.hs
+++ b/src/Hasklepias/FeatureEvents.hs
@@ -39,6 +39,7 @@
     , isBirthYear
     , isGenderFact
     , isStateFact
+    , isEnrollment
     , filterByDomain
 
     -- ** Manipulating Dates
@@ -275,6 +276,11 @@
 isStateFact :: Domain -> Bool 
 isStateFact (Demographics (DemographicsFacts (DemographicsInfo State _))) = True
 isStateFact _ = False
+
+-- | Predicate for State facts
+isEnrollment :: Domain -> Bool 
+isEnrollment (Enrollment _) = True
+isEnrollment _ = False
 
 -- | Filters a container of 'Event's by the 'Domain'.
 filterByDomain :: (Witherable f) => (Domain -> Bool) -> f (Event a) -> f (Event a)
diff --git a/src/Hasklepias/Templates.hs b/src/Hasklepias/Templates.hs
new file mode 100644
--- /dev/null
+++ b/src/Hasklepias/Templates.hs
@@ -0,0 +1,16 @@
+{-|
+Module      : Exports Hasklepias templates
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+{-# OPTIONS_HADDOCK hide #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+
+module Hasklepias.Templates (
+   module Hasklepias.Templates.Features
+
+) where
+
+import Hasklepias.Templates.Features
diff --git a/src/Hasklepias/Templates/Features.hs b/src/Hasklepias/Templates/Features.hs
new file mode 100644
--- /dev/null
+++ b/src/Hasklepias/Templates/Features.hs
@@ -0,0 +1,16 @@
+{-|
+Module      : Exports Hasklepias templates
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+{-# OPTIONS_HADDOCK hide #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+
+module Hasklepias.Templates.Features (
+   module Hasklepias.Templates.Features.Enrollment
+
+) where
+
+import Hasklepias.Templates.Features.Enrollment (defIsEnrolled, defContinuousEnrollment)
diff --git a/src/Hasklepias/Templates/Features/Enrollment.hs b/src/Hasklepias/Templates/Features/Enrollment.hs
new file mode 100644
--- /dev/null
+++ b/src/Hasklepias/Templates/Features/Enrollment.hs
@@ -0,0 +1,216 @@
+{-|
+Module      : Enrollment Features Templates 
+Description : Templates for Features pertaining to enrollment
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+-}
+{-# OPTIONS_HADDOCK hide #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+
+module Hasklepias.Templates.Features.Enrollment (
+    defIsEnrolled 
+  , defContinuousEnrollment
+  , defEnrollmentTests
+) where
+
+import Control.Applicative              ( Applicative(..) )
+import GHC.Int                          ( Int )
+import GHC.TypeLits                     ( KnownSymbol )
+import GHC.Show                         ( Show )
+import Flow                             ( (|>), (.>) )
+import IntervalAlgebra
+import IntervalAlgebra.IntervalUtilities ( combineIntervals )
+import IntervalAlgebra.PairedInterval   ( intervals )
+import Witherable                       ( Witherable )
+import Data.Eq                          ( Eq )
+import Data.Foldable                    (Foldable(..), any)
+import Data.Function                    ( ($), (.) )
+import Data.Functor                     ( Functor(.. ) )
+import Data.Maybe                       ( Maybe )
+import Data.Monoid                      ( Monoid(..) )
+import Data.Text                        ( Text )
+import Data.Tuple                       ( uncurry )                     
+import Test.Tasty                       ( testGroup, TestName, TestTree )
+import Test.Tasty.HUnit                 ( testCase )
+
+import EventData                        ( Event
+                                        , Domain(..)
+                                        , EnrollmentFacts(..)
+                                        , event
+                                        , context
+                                        )
+import Features.Compose                 ( Feature
+                                        , Definition(..)
+                                        , Define(..)
+                                        , Eval(..)
+                                        , makeFeature )
+import Hasklepias.FeatureEvents         ( allGapsWithinLessThanDuration
+                                        , makeConceptsFilter
+                                        , filterByDomain
+                                        , isEnrollment, lookback )
+import Hasklepias.Templates.TestUtilities
+                                        ( makeAssertion
+                                        , TemplateTestCase(..) )
+import Hasklepias.Misc                  ( F )
+import Cohort.Index                     ( Index(..) )
+import Cohort.Criteria                  ( Status(..), includeIf )
+
+
+{-| Is Enrolled
+
+TODO: describe this
+
+-}
+defIsEnrolled ::
+  ( Intervallic i0 a
+  , Monoid (container (Interval a))
+  , Applicative container
+  , Witherable container) =>
+  Definition
+  (   Feature indexName  (Index i0 a)
+   -> Feature eventsName (container (Event a))
+   -> Feature varName     Status )
+defIsEnrolled =
+  define
+      (\index ->
+           filterByDomain isEnrollment
+        .> combineIntervals
+        .> any (concur index)
+        .> includeIf
+      )
+
+makeIsEnrolledTestInputs :: (IntervalSizeable a b) =>
+     TestName
+  -> b 
+  -> a
+  -> [Event a]
+  -> Status
+  -> TemplateTestCase (F "index" (Index Interval a), F "events" [Event a]) Status
+makeIsEnrolledTestInputs name dur bgn e s = 
+  MkTemplateTestCase name (pure (MkIndex $ beginerval dur bgn), pure e) (pure s)
+
+makeEnrollmentEvent :: (IntervalSizeable a b) => b -> a -> Event a
+makeEnrollmentEvent dur bgn = 
+  event (beginerval dur bgn) (context ( Enrollment EnrollmentFacts) mempty)
+
+defIsEnrolledTestCases :: [TemplateTestCase
+   (F "index" (Index Interval Int), F "events" [Event Int]) Status]
+defIsEnrolledTestCases = [ 
+      f "Exclude if no events" 1 (0::Int) []   Exclude
+    , f "Exclude if only interval meets" 1 (0::Int) [g 5 1]  Exclude
+    , f "Include if concurring interval" 1 (0::Int) [g 5 (-1)] Include
+    , f "Include if concurring interval" 1 (0::Int) [g 2 (-1), g 5 1]  Include 
+  ] where f = makeIsEnrolledTestInputs
+          g = makeEnrollmentEvent
+
+defIsEnrolledTests :: TestTree
+defIsEnrolledTests = testGroup "Tests of isEnrolled template"
+     ( fmap (\x -> testCase (getTestName x) (makeAssertion x defIsEnrolled) )
+       defIsEnrolledTestCases )
+
+
+{-| Continuous Enrollment 
+
+TODO: describe this
+-}
+defContinuousEnrollment ::
+  ( Monoid (container (Interval a))
+  , Monoid (container (Maybe (Interval a)))
+  , Applicative container
+  , Witherable container
+  , IntervalCombinable i1 a
+  , IntervalSizeable a b) =>
+    (Index i0 a -> i1 a) -- ^ function which maps index interval to interval in which to assess enrollment
+  -> b                   -- ^ duration of allowable gap between enrollment intervals
+  -> Definition
+  (   Feature indexName  (Index i0 a)
+   -> Feature eventsName (container (Event a))
+   -> Feature prevName    Status
+   -> Feature varName     Status )
+defContinuousEnrollment formInterval allowableGap =
+  define
+    (\index events prevStatus ->
+      case prevStatus of
+        Exclude -> Exclude
+        Include -> includeIf
+          ( allGapsWithinLessThanDuration
+                allowableGap
+                (formInterval index)
+                (combineIntervals $ filterByDomain isEnrollment events))
+    )
+
+makeContinuousEnrollmentTestInputs :: (IntervalSizeable a b) =>
+     TestName
+  -> b 
+  -> a
+  -> [Event a]
+  -> Status
+  -> Status
+  -> TemplateTestCase (F "index" (Index Interval a), F "events" [Event a], F "prev" Status) Status
+makeContinuousEnrollmentTestInputs name dur bgn e prev s = 
+  MkTemplateTestCase name (pure (MkIndex $ beginerval dur bgn), pure e, pure prev) (pure s)
+
+defContinuousEnrollmentTestCases :: [TemplateTestCase
+   (F "index" (Index Interval Int), F "events" [Event Int], F "prev" Status) Status]
+defContinuousEnrollmentTestCases = [ 
+      f "Exclude if previously excluded" 1 (0::Int) []  Exclude  Exclude
+    , f "Exclude if no events" 1 (0::Int) []  Include  Exclude
+      {-
+                  -           <- Index
+         ----------           <- Baseline
+         ---     ---          <- Enrollment
+        |--------------|
+      -}
+    , f "Exclude if gap >= 3" 1 (10::Int) [g 3 1, g 3 9]  Include Exclude
+      {-
+                  -           <- Index
+        ----------            <- Baseline
+         ------               <- Enrollment
+        |--------------|
+      -}
+    , f "Exclude if gap >= 3" 1 (10::Int) [g 6 1]   Include Exclude
+        {-
+                  -           <- Index
+         ----------           <- Baseline
+              -------         <- Enrollment
+        |--------------|
+      -}
+    , f "Exclude if gap >= 3" 1 (10::Int) [g 7 6]   Include Exclude
+      {-
+                  -           <- Index
+         ----------           <- Baseline
+         --  -------          <- Enrollment
+        |--------------|
+      -}
+    , f "Include if gaps less than 3" 1 (10::Int) [g 2 1, g 7 5]  Include Include
+      {-
+                  -           <- Index
+         ----------           <- Baseline
+          -------             <- Enrollment
+        |--------------|
+      -}
+    , f "Include if gaps less than 3" 1 (10::Int) [g 7 2]  Include Include
+        {-
+                  -           <- Index
+         ----------           <- Baseline
+         -----                <- Enrollment
+             ----
+        |--------------|
+      -}
+    , f "Include if gaps less than 3" 1 (10::Int) [g 5 1, g 4 4]  Include Include
+  ] where f = makeContinuousEnrollmentTestInputs
+          g = makeEnrollmentEvent
+
+defContinuousEnrollmentTests :: TestTree
+defContinuousEnrollmentTests = testGroup "Tests of continuous enrollment template"
+     ( fmap (\x -> testCase (getTestName x) 
+          (makeAssertion x (defContinuousEnrollment (lookback 10) 3)) )
+           defContinuousEnrollmentTestCases )
+
+defEnrollmentTests :: TestTree
+defEnrollmentTests = testGroup "" [defIsEnrolledTests, defContinuousEnrollmentTests]
diff --git a/src/Hasklepias/Templates/TestUtilities.hs b/src/Hasklepias/Templates/TestUtilities.hs
new file mode 100644
--- /dev/null
+++ b/src/Hasklepias/Templates/TestUtilities.hs
@@ -0,0 +1,46 @@
+{-|
+Module      : Functions and types for creating tests for templates 
+Description : Misc types and functions useful in Hasklepias.
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+These functions may be moved to more appropriate modules in future versions.
+-}
+{-# OPTIONS_HADDOCK hide #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+
+module Hasklepias.Templates.TestUtilities (
+    TemplateTestCase(..)
+  , evalTestCase
+  , makeAssertion
+) where
+
+import Data.Eq                          ( Eq )
+import Data.Tuple                       ( uncurry )
+import GHC.Show                         ( Show )
+import Features.Compose                 ( Feature
+                                        , Definition(..)
+                                        , Define(..)
+                                        , Eval(..) )
+import Test.Tasty                       ( TestName )
+import Test.Tasty.HUnit                 ( (@=?), Assertion )
+
+data TemplateTestCase a b = MkTemplateTestCase {
+    getTestName :: TestName
+  , getInputs :: a
+  , getTruth  :: Feature "result" b
+  } deriving (Eq, Show)
+
+evalTestCase :: Eval def args return => 
+  TemplateTestCase args b 
+  -> Definition def 
+  -> ( return, Feature "result" b )
+evalTestCase (MkTemplateTestCase _ inputs truth) def = ( eval def inputs, truth )
+
+makeAssertion :: (Eq b, Show b, Eval def args (Feature "result" b)) =>
+  TemplateTestCase args b -> Definition def -> Assertion
+makeAssertion x def = uncurry (@=?) (evalTestCase x def)
diff --git a/src/Hasklepias/Templates/Tests.hs b/src/Hasklepias/Templates/Tests.hs
new file mode 100644
--- /dev/null
+++ b/src/Hasklepias/Templates/Tests.hs
@@ -0,0 +1,24 @@
+{-|
+Module      : Functions and types for creating tests for templates 
+Description : Misc types and functions useful in Hasklepias.
+Copyright   : (c) NoviSci, Inc 2020
+License     : BSD3
+Maintainer  : bsaul@novisci.com
+
+These functions may be moved to more appropriate modules in future versions.
+-}
+{-# OPTIONS_HADDOCK hide #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+
+module Hasklepias.Templates.Tests (
+   templateTests
+) where
+
+import Test.Tasty                               ( testGroup, TestTree )                       
+import Hasklepias.Templates.Features.Enrollment ( defEnrollmentTests )
+
+templateTests :: TestTree
+templateTests = testGroup "tests of feature templates" [defEnrollmentTests]
diff --git a/template-test/Main.hs b/template-test/Main.hs
new file mode 100644
--- /dev/null
+++ b/template-test/Main.hs
@@ -0,0 +1,9 @@
+module Main(
+   main
+) where
+
+import Test.Tasty                 ( defaultMain )
+import Hasklepias.Templates.Tests ( templateTests )
+
+main :: IO ()
+main =  defaultMain templateTests