diff --git a/.github/workflows/maintenance.yaml b/.github/workflows/maintenance.yaml
index 26023ef..5393e4d 100644
--- a/.github/workflows/maintenance.yaml
+++ b/.github/workflows/maintenance.yaml
@@ -21,7 +21,7 @@ jobs:
                    sudo bash ./llvm.sh 19                                            &&
                    (sudo rm /usr/bin/clang-format || exit 0)                         &&
                    sudo apt -y install clang-format-19
-            - run: gradle format
+            - run: gradle --no-daemon format
 
     build:
         timeout-minutes: 10
@@ -33,4 +33,4 @@ jobs:
                   java-version: '21'
                   distribution: 'temurin'
 
-            - run: ./gradlew --no-daemon build
+            - run: cabal update && ./gradlew --no-daemon build
diff --git a/build.gradle.kts b/build.gradle.kts
index 4e3304a..fc86786 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -112,8 +112,11 @@ pitest {
 // Test generation
 
 tasks.register<Exec>("generateQuickCheckTests") {
+    File("src/facadetests/java/MakeItFit").mkdirs()
+    dependsOn(tasks.jar)
     workingDir = file("src/testgen")
-    commandLine = listOf("cabal", "run")
+    commandLine =
+        listOf("cabal", "run", "testgen", "--", "../facadetests/java/MakeItFit/MakeItFitTest.java")
 }
 
 tasks.register<JavaExec>("generateEvoSuiteTests") {
@@ -139,11 +142,21 @@ tasks.register<JavaExec>("generateEvoSuiteTests") {
 
 // Other tasks
 
+tasks.named<Task>("build") {
+    finalizedBy(tasks.named<Task>("buildHaskell"))
+}
+
+tasks.register<Exec>("buildHaskell") {
+    workingDir = file("src/testgen")
+    commandLine = listOf("cabal", "build")
+}
+
 tasks.named<JavaExec>("run") {
     standardInput = System.`in`
 }
 
 tasks.register<Exec>("repl") {
+    dependsOn(tasks.jar)
     workingDir = file("src/testgen")
     commandLine = listOf("cabal", "repl")
     standardInput = System.`in`
diff --git a/src/testgen/testgen.cabal b/src/testgen/testgen.cabal
index caa9267..66138b1 100644
--- a/src/testgen/testgen.cabal
+++ b/src/testgen/testgen.cabal
@@ -23,4 +23,4 @@ executable testgen
     build-depends:
         base >=4.15.1.0 && <5,
         QuickCheck ^>=2.15.0.1,
-        process ^>=1.6.26.1
+        process ^>=1.6.25.0
diff --git a/src/testgen/testgen/FacadeTemplates.hs b/src/testgen/testgen/FacadeTemplates.hs
index f34954e..9fab41b 100644
--- a/src/testgen/testgen/FacadeTemplates.hs
+++ b/src/testgen/testgen/FacadeTemplates.hs
@@ -13,12 +13,13 @@
 -- limitations under the License.
 
 module FacadeTemplates (
-    equalityTemplate
+    equalityTemplate,
+    emailTemplate
   ) where
 
-import Java (assertEquals, toJavaExpression)
-import TestTemplate (TestTemplate, genToTestTemplate)
-import Test.QuickCheck (Gen, arbitrary)
+import Java (assertEquals, runJava, toJavaExpression)
+import TestTemplate (TestTemplate(..), genToTestTemplate)
+import Test.QuickCheck (Gen, arbitrary, elements, generate, listOf)
 
 equalityTestGenerator :: Gen [String]
 equalityTestGenerator = do
@@ -32,3 +33,25 @@ equalityTestGenerator = do
 
 equalityTemplate :: TestTemplate
 equalityTemplate = genToTestTemplate "equals" equalityTestGenerator 3
+
+genEmail :: Gen String
+genEmail = do
+  before <- listOf $ elements (['a'..'z'] ++ ['A'..'Z'] ++ ['0'..'9'])
+  after <- listOf $ elements (['a'..'z'] ++ ['A'..'Z'] ++ ['0'..'9'])
+  return $ before ++ "@" ++ after ++ ".com"
+
+emailTestGenerator :: IO [String]
+emailTestGenerator = do
+  email <- generate $ genEmail
+  resultLines <- runJava
+    [
+      "import MakeItFit.utils.EmailValidator;"
+    , "System.out.println(EmailValidator.isValidEmail(" ++ toJavaExpression email ++ "));"
+    ]
+  return
+    [
+      assertEquals (toJavaExpression email) (last resultLines)
+    ]
+
+emailTemplate :: TestTemplate
+emailTemplate = TestTemplate "validEmail" emailTestGenerator 1
diff --git a/src/testgen/testgen/Java.hs b/src/testgen/testgen/Java.hs
index 9fbd4a9..d107c76 100644
--- a/src/testgen/testgen/Java.hs
+++ b/src/testgen/testgen/Java.hs
@@ -23,12 +23,27 @@ module Java
   , assertTrue
   , assertEquals
   , assertSame
-  , assertThrows) where
+  , assertThrows
+  , runJava
+  ) where
 
 import Data.Char (isAscii, ord)
-import Data.List (intercalate)
+import Data.List (intercalate, isPrefixOf)
 import Numeric (showHex)
 
+import System.Process
+  (
+    StdStream(CreatePipe)
+  , createProcess
+  , proc
+  , std_in
+  , std_out
+  , std_err
+  , waitForProcess
+  )
+import System.IO (Handle, hClose, hGetContents, hPutStr)
+import Control.Exception (bracket, evaluate)
+
 -- JavaData definition
 class JavaData a where
   -- | Gets the equivalent Java name for this Haskell type
@@ -181,3 +196,32 @@ assertThrows e b =
     "    }"
   , ");"
   ]
+
+-- JVM interop
+
+-- | Runs Java code with classes the project classes loaded
+runJava :: [String]    -- ^ Java statements
+        -> IO [String] -- ^ Lines output by the statements
+runJava statements = do
+  (Just stdin, Just stdout, Just stderr, process) <- createProcess
+    (proc "jshell" ["--class-path=../../build/libs/ATS.jar"])
+    { std_in = CreatePipe, std_out = CreatePipe, std_err = CreatePipe }
+
+  bracket
+    (return ())
+    (\_ -> do
+      hClose stdin
+      hClose stdout
+      hClose stderr
+    )
+    (\_ -> do
+      hPutStr stdin (unlines statements)
+      hClose stdin
+
+      output <- hGetContents stdout
+      evaluate (length output) -- Force deep strict evaluation
+      let outputLines = lines output
+
+      waitForProcess process
+      return $ filter (not . isPrefixOf "|  ") outputLines
+    )
diff --git a/src/testgen/testgen/Main.hs b/src/testgen/testgen/Main.hs
index cfd672e..bf6a6c9 100644
--- a/src/testgen/testgen/Main.hs
+++ b/src/testgen/testgen/Main.hs
@@ -14,5 +14,19 @@
 
 module Main where
 
+import Java (runJava)
+import System.Environment (getArgs)
+import System.Exit (ExitCode(ExitFailure), exitWith)
+import System.IO (hPutStrLn, stderr)
+import TestClass (generateTestClass)
+
 main :: IO ()
-main = putStrLn "Hello, Haskell!"
+main = do
+  args <- getArgs
+  case args of
+    [file] -> do
+      test <- generateTestClass
+      writeFile file test
+    _ -> do
+      hPutStrLn stderr "Usage: cabal run testgen -- OutputFile.java"
+      exitWith (ExitFailure 1)
diff --git a/src/testgen/testgen/TestClass.hs b/src/testgen/testgen/TestClass.hs
index 97d0668..76fe043 100644
--- a/src/testgen/testgen/TestClass.hs
+++ b/src/testgen/testgen/TestClass.hs
@@ -39,8 +39,12 @@ generateUnformattedTestClass = do
   tests <- generateTests
   return
     $ concat
-        [ [ "import java.util.Arrays;"
+        [ [ "package MakeItFit;"
+          , ""
+          , "import java.util.Arrays;"
           , "import java.util.List;"
+          , "import org.junit.jupiter.api.Test;"
+          , "import static org.junit.jupiter.api.Assertions.*;"
           , ""
           , "import MakeItFit.users.User;"
           , ""