diff --git a/package.yaml b/package.yaml
index 893802c..cc42a10 100644
--- a/package.yaml
+++ b/package.yaml
@@ -159,3 +159,12 @@ benchmarks:
     - casa-client
     ghc-options:
     - -O2
+
+tests:
+  unit-tests:
+    main: main.hs
+    source-dirs: unit-tests
+    dependencies:
+    - stackage-server
+    - hspec
+    - pantry
diff --git a/stack.yaml b/stack.yaml
index fd33610..7fe6448 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -5,6 +5,10 @@ extra-deps:
 - classy-prelude-yesod-1.5.0
 - unliftio-core-0.1.2.0
 - yesod-gitrepo-0.3.0
+- hspec-2.11.1
+- hspec-core-2.11.1
+- hspec-discover-2.11.1
+- hspec-expectations-0.8.3
 
 drop-packages:
 - Cabal
diff --git a/unit-tests/main.hs b/unit-tests/main.hs
new file mode 100644
index 0000000..592b734
--- /dev/null
+++ b/unit-tests/main.hs
@@ -0,0 +1,28 @@
+import Pantry (parseVersionThrowing, parsePackageNameThrowing)
+import Pantry.Internal.Stackage (VersionP(VersionP), PackageNameP(PackageNameP))
+import Stackage.Snapshot.Diff (SnapshotDiff, snapshotDiff, toDiffList)
+
+import Test.Hspec (Spec, describe, hspec, it, shouldBe)
+
+snapshotDiffLength :: SnapshotDiff -> Int
+snapshotDiffLength = length . toDiffList
+
+main :: IO ()
+main = do
+  booleanName <- PackageNameP <$> parsePackageNameThrowing "Boolean"
+  booleanVer <- VersionP <$> parseVersionThrowing "0.2.4"
+  bookkeepingName <- PackageNameP <$> parsePackageNameThrowing "bookkeeping"
+  bookkeepingVer <- VersionP <$> parseVersionThrowing "0.4.0.1"
+
+  let
+    boolean = (booleanName, booleanVer)
+    bookkeeping = (bookkeepingName, bookkeepingVer)
+
+  hspec $
+    describe "Packages with upper case characters" $
+      describe "Removal of bookkeeping package is one change" $ do
+        it "[Boolean, bookkeeping] -> [Boolean]" $
+          snapshotDiffLength (snapshotDiff [boolean, bookkeeping] [boolean]) `shouldBe` 1
+
+        it "[bookkeeping, Boolean] -> [Boolean]" $
+          snapshotDiffLength (snapshotDiff [bookkeeping, boolean] [boolean]) `shouldBe` 1