diff --git a/shellify.cabal b/shellify.cabal
--- a/shellify.cabal
+++ b/shellify.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               shellify
-version:            0.10.0.2
+version:            0.10.0.3
 
 author: Daniel Rolls
 maintainer: daniel.rolls.27@googlemail.com
@@ -16,6 +16,7 @@
 extra-doc-files:
         CHANGELOG.md
 tested-with:
+    GHC == 9.2.4,
     GHC == 9.2.8,
     GHC == 9.6.2
 
@@ -26,7 +27,7 @@
 common deps
     default-language: GHC2021
     build-depends:
-        base >=4.16.4.0 && <4.19,
+        base >=4.16 && <4.19,
         raw-strings-qq >=1.1 && <1.2,
         text >=1.2.5.0 && <2.1
 
@@ -71,7 +72,8 @@
     main-is: Spec.hs
     hs-source-dirs: test
     other-modules:
-        Paths_shellify
+        Paths_shellify,
+        TestHelpers
     ghc-options: -threaded -rtsopts -with-rtsopts=-N
     build-depends:
         hspec >=2.9.7 && <2.12,
diff --git a/test/TestHelpers.hs b/test/TestHelpers.hs
new file mode 100644
--- /dev/null
+++ b/test/TestHelpers.hs
@@ -0,0 +1,59 @@
+module TestHelpers where
+
+import Prelude hiding (last, putStrLn, readFile, reverse, tail, words)
+import Data.Bool (bool)
+import Data.Text (isInfixOf, last, reverse, tail, Text(), unpack, words)
+import Data.Text.IO (putStrLn, readFile)
+import Test.Hspec (Expectation(), expectationFailure, it, shouldBe, shouldContain)
+
+import Options
+import Shellify
+import TemplateGeneration
+
+shouldReturnSubstring shellifyOutput expectedSubstring =
+    either
+      ((`shouldContain` expectedSubstring) . unpack)
+      (const (expectationFailure "expected Left but got Right"))
+      shellifyOutput
+
+shellifyWithArgs :: Text -> Either Text [(Text, Text)]
+shellifyWithArgs = parseOptionsAndCalculateExpectedFiles db "nix-shellify" . words
+
+shouldReturnShellAndFlakeTextDefinedBy result expectedOutput =
+     it "should produce the expected shell.nix and flake.nix" $
+       do expShell <- readNixTemplate (shellFile expectedOutput)
+          expFlake <- readNixTemplate (flakeFile expectedOutput)
+          result `shouldBe`
+              Right [("shell.nix", expShell),("flake.nix", expFlake)]
+
+shouldReturnShellTextDefinedBy result expectedOutput =
+     it "should produce the expected shell.nix" $
+       do expShell <- readNixTemplate (shellFile expectedOutput)
+          either
+            (const $ expectationFailure "Expected Right but got Left")
+            (\((fileName, shellNixOutput):_) ->
+                  do shellNixOutput `shouldBe` expShell
+                     fileName `shouldBe` "shell.nix")
+            result
+
+theOptions = options "nix-shellify" . words
+
+shouldResultInPackages :: Text -> [Text] -> Expectation
+shouldResultInPackages parameters packages =
+     theOptions parameters
+       `shouldBe`
+     Right def{packages=packages}
+
+instance Show Options
+
+readNixTemplate :: FilePath -> IO Text
+readNixTemplate fileName =
+    stripTrailingNewline <$> readFile ("test/outputs/" <> fileName)
+    where stripTrailingNewline f = bool id stripLastChar (lastCharIsNewline f) f
+          lastCharIsNewline = (== '\n') . last
+          stripLastChar = reverse . tail . reverse
+
+flakeFile = (<> "-flake.nix")
+shellFile = (<> "-shell.nix")
+
+db = "global flake:agda github:agda/agda\nglobal flake:arion github:hercules-ci/arion\nglobal flake:blender-bin github:edolstra/nix-warez?dir=blender\nglobal flake:composable github:ComposableFi/composable\nglobal flake:dreampkgs github:nix-community/dreampkgs\nglobal flake:dwarffs github:edolstra/dwarffs\nglobal flake:emacs-overlay github:nix-community/emacs-overlay\nglobal flake:fenix github:nix-community/fenix\nglobal flake:flake-parts github:hercules-ci/flake-parts\nglobal flake:flake-utils github:numtide/flake-utils\nglobal flake:gemini github:nix-community/flake-gemini\nglobal flake:hercules-ci-effects github:hercules-ci/hercules-ci-effects\nglobal flake:hercules-ci-agent github:hercules-ci/hercules-ci-agent\nglobal flake:home-manager github:nix-community/home-manager\nglobal flake:hydra github:NixOS/hydra\nglobal flake:mach-nix github:DavHau/mach-nix\nglobal flake:nimble github:nix-community/flake-nimble\nglobal flake:nix github:NixOS/nix\nglobal flake:nix-darwin github:LnL7/nix-darwin\nglobal flake:nixops github:NixOS/nixops\nglobal flake:nixos-hardware github:NixOS/nixos-hardware\nglobal flake:nixos-homepage github:NixOS/nixos-homepage\nglobal flake:nixos-search github:NixOS/nixos-search\nglobal flake:nur github:nix-community/NUR\nglobal flake:nixpkgs github:NixOS/nixpkgs/nixpkgs-unstable\nglobal flake:templates github:NixOS/templates\nglobal flake:patchelf github:NixOS/patchelf\nglobal flake:poetry2nix github:nix-community/poetry2nix\nglobal flake:nix-serve github:edolstra/nix-serve\nglobal flake:nickel github:tweag/nickel\nglobal flake:bundlers github:NixOS/bundlers\nglobal flake:pridefetch github:SpyHoodle/pridefetch\nglobal flake:systems github:nix-systems/default\nglobal flake:helix github:helix-editor/helix\nglobal flake:sops-nix github:Mic92/sops-nix\n" :: Text