diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,34 @@
+Copyright (c) 2023 Torsten Schmits
+
+Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+following conditions are met:
+
+  1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+  disclaimer.
+  2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+  disclaimer in the documentation and/or other materials provided with the distribution.
+
+Subject to the terms and conditions of this license, each copyright holder and contributor hereby grants to those
+receiving rights under this license a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except
+for failure to satisfy the conditions of this license) patent license to make, have made, use, offer to sell, sell,
+import, and otherwise transfer this software, where such license applies only to those patent claims, already acquired
+or hereafter acquired, licensable by such copyright holder or contributor that are necessarily infringed by:
+
+  (a) their Contribution(s) (the licensed copyrights of copyright holders and non-copyrightable additions of
+  contributors, in source or binary form) alone; or
+  (b) combination of their Contribution(s) with the work of authorship to which such Contribution(s) was added by such
+  copyright holder or contributor, if, at the time the Contribution is added, such addition causes such combination to
+  be necessarily infringed. The patent license shall not apply to any other combinations which include the Contribution.
+
+Except as expressly stated above, no rights or licenses from any copyright holder or contributor is granted under this
+license, whether expressly, by implication, estoppel or otherwise.
+
+DISCLAIMER
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/lib/Polysemy/Hasql/Test.hs b/lib/Polysemy/Hasql/Test.hs
new file mode 100644
--- /dev/null
+++ b/lib/Polysemy/Hasql/Test.hs
@@ -0,0 +1,7 @@
+module Polysemy.Hasql.Test (
+  module Polysemy.Hasql.Test.Run,
+  module Polysemy.Hasql.Test.Migration,
+) where
+
+import Polysemy.Hasql.Test.Run (integrationTest, integrationTestWith, runIntegrationTestWith, dbConfig)
+import Polysemy.Hasql.Test.Migration
diff --git a/lib/Polysemy/Hasql/Test/Migration.hs b/lib/Polysemy/Hasql/Test/Migration.hs
new file mode 100644
--- /dev/null
+++ b/lib/Polysemy/Hasql/Test/Migration.hs
@@ -0,0 +1,33 @@
+module Polysemy.Hasql.Test.Migration where
+
+import qualified Data.Text as Text
+import Hedgehog.Internal.Property (failWith)
+import Path (reldir)
+import qualified Polysemy.Test as Test
+import Polysemy.Test (Hedgehog, Test, liftH)
+import Sqel.Data.Migration (Migrations)
+import Sqel.Migration.Consistency (migrationConsistency)
+
+testMigration' ::
+  ∀ migs r .
+  Members [Test, Hedgehog IO, Embed IO] r =>
+  Migrations (Sem r) migs ->
+  Bool ->
+  Sem r ()
+testMigration' migs write =
+  withFrozenCallStack do
+    dir <- Test.fixturePath [reldir|migration|]
+    migrationConsistency dir migs write >>= \case
+      Just errors ->
+        liftH (failWith Nothing (toString (Text.intercalate "\n" (toList errors))))
+      Nothing -> unit
+
+testMigration ::
+  ∀ migs r .
+  Members [Test, Hedgehog IO, Embed IO] r =>
+  Migrations (Sem r) migs ->
+  Bool ->
+  Sem r ()
+testMigration migs write =
+  withFrozenCallStack do
+    testMigration' migs write
diff --git a/lib/Polysemy/Hasql/Test/Run.hs b/lib/Polysemy/Hasql/Test/Run.hs
new file mode 100644
--- /dev/null
+++ b/lib/Polysemy/Hasql/Test/Run.hs
@@ -0,0 +1,116 @@
+module Polysemy.Hasql.Test.Run where
+
+import Conc (interpretMaskFinal, interpretRace)
+import Data.UUID (UUID)
+import Exon (exon)
+import Hasql.Session (QueryError)
+import Hedgehog (TestT)
+import Hedgehog.Internal.Property (Failure)
+import Log (Severity (Error), interpretLogStdoutLevelConc)
+import Polysemy.Db (interpretRandom)
+import Polysemy.Db.Data.DbConfig (DbConfig (DbConfig))
+import Polysemy.Db.Data.DbConnectionError (DbConnectionError)
+import Polysemy.Db.Data.DbError (DbError)
+import Polysemy.Db.Data.InitDbError (InitDbError)
+import Polysemy.Db.Effect.Random (Random)
+import qualified Polysemy.Test as Hedgehog
+import Polysemy.Test (Hedgehog, Test, runTestAuto)
+import Polysemy.Test.Data.TestError (TestError)
+import Time (GhcTime, interpretTimeGhc)
+import System.Environment (lookupEnv)
+
+import Polysemy.Hasql.Test.Database (TestConnectionEffects, withTestConnection)
+
+type DbErrors =
+  [
+    Stop DbConnectionError,
+    Stop DbError,
+    Stop QueryError,
+    Stop Text,
+    Error InitDbError,
+    Error DbError
+  ]
+
+type TestEffects =
+  DbErrors ++ [
+    GhcTime,
+    Random UUID,
+    Log,
+    Error Text,
+    Mask,
+    Race,
+    Async,
+    Test,
+    Fail,
+    Error TestError,
+    Hedgehog IO,
+    Error Failure,
+    Embed IO,
+    Resource,
+    Final IO
+  ]
+
+dbConfig ::
+  MonadIO m =>
+  String ->
+  Text ->
+  m (Maybe DbConfig)
+dbConfig envPrefix name = do
+  traverse cons =<< (liftIO (lookupEnv [exon|#{envPrefix}_test_host|]))
+  where
+    cons host = do
+      port <- parsePort =<< (fromMaybe "4321" <$> liftIO (lookupEnv [exon|#{envPrefix}_test_port|]))
+      pure (DbConfig (fromString host) port (fromText name) (fromText name) (fromText name))
+    parsePort p =
+      case readMaybe p of
+        Just a -> pure a
+        Nothing -> error [exon|invalid port in env var $#{envPrefix}_test_port: #{p}|]
+
+runIntegrationTestWith ::
+  Members [Error Text, Embed IO] r =>
+  HasCallStack =>
+  String ->
+  Text ->
+  (DbConfig -> Sem (DbErrors ++ r) ()) ->
+  Sem r ()
+runIntegrationTestWith envPrefix name run =
+  withFrozenCallStack do
+    dbConfig envPrefix name >>= \case
+      Just conf ->
+        mapError @DbError @Text show $
+        mapError @InitDbError @Text show $
+        stopToError @Text $
+        mapStop @QueryError @Text show $
+        mapStop @DbError @Text show $
+        mapStop @DbConnectionError @Text show $
+        run conf
+      Nothing ->
+        unit
+
+integrationTestWith ::
+  HasCallStack =>
+  String ->
+  Text ->
+  (DbConfig -> Sem TestEffects ()) ->
+  TestT IO ()
+integrationTestWith envPrefix name run =
+  withFrozenCallStack $ runTestAuto do
+    r <- asyncToIOFinal $
+      interpretRace $
+      interpretMaskFinal $
+      runError @Text $
+      interpretLogStdoutLevelConc (Just Error) $
+      interpretRandom $
+      interpretTimeGhc $
+      runIntegrationTestWith envPrefix name run
+    Hedgehog.evalEither r
+
+integrationTest ::
+  HasCallStack =>
+  String ->
+  Text ->
+  Sem (TestConnectionEffects ++ TestEffects) () ->
+  TestT IO ()
+integrationTest envPrefix name thunk =
+  withFrozenCallStack do
+    integrationTestWith envPrefix name \ conf -> withTestConnection conf thunk
diff --git a/polysemy-hasql-test.cabal b/polysemy-hasql-test.cabal
new file mode 100644
--- /dev/null
+++ b/polysemy-hasql-test.cabal
@@ -0,0 +1,202 @@
+cabal-version: 2.2
+
+-- This file has been generated from package.yaml by hpack version 0.35.0.
+--
+-- see: https://github.com/sol/hpack
+
+name:           polysemy-hasql-test
+version:        0.0.1.0
+synopsis:       Test utilities for polysemy-hasql
+description:    See https://hackage.haskell.org/package/polysemy-hasql-test/docs/Polysemy-Hasql-Test.html
+category:       Database
+author:         Torsten Schmits
+maintainer:     hackage@tryp.io
+copyright:      2023 Torsten Schmits
+license:        BSD-2-Clause-Patent
+license-file:   LICENSE
+build-type:     Simple
+
+library
+  exposed-modules:
+      Polysemy.Hasql.Test
+      Polysemy.Hasql.Test.Migration
+      Polysemy.Hasql.Test.Run
+  hs-source-dirs:
+      lib
+  default-extensions:
+      StandaloneKindSignatures
+      AllowAmbiguousTypes
+      ApplicativeDo
+      BangPatterns
+      BinaryLiterals
+      BlockArguments
+      ConstraintKinds
+      DataKinds
+      DefaultSignatures
+      DeriveAnyClass
+      DeriveDataTypeable
+      DeriveFoldable
+      DeriveFunctor
+      DeriveGeneric
+      DeriveLift
+      DeriveTraversable
+      DerivingStrategies
+      DerivingVia
+      DisambiguateRecordFields
+      DoAndIfThenElse
+      DuplicateRecordFields
+      EmptyCase
+      EmptyDataDecls
+      ExistentialQuantification
+      FlexibleContexts
+      FlexibleInstances
+      FunctionalDependencies
+      GADTs
+      GeneralizedNewtypeDeriving
+      InstanceSigs
+      KindSignatures
+      LambdaCase
+      LiberalTypeSynonyms
+      MultiParamTypeClasses
+      MultiWayIf
+      NamedFieldPuns
+      OverloadedLabels
+      OverloadedLists
+      OverloadedStrings
+      PackageImports
+      PartialTypeSignatures
+      PatternGuards
+      PatternSynonyms
+      PolyKinds
+      QuantifiedConstraints
+      QuasiQuotes
+      RankNTypes
+      RecordWildCards
+      RecursiveDo
+      RoleAnnotations
+      ScopedTypeVariables
+      StandaloneDeriving
+      TemplateHaskell
+      TupleSections
+      TypeApplications
+      TypeFamilies
+      TypeFamilyDependencies
+      TypeOperators
+      TypeSynonymInstances
+      UndecidableInstances
+      UnicodeSyntax
+      ViewPatterns
+  ghc-options: -Wall -Wredundant-constraints -Wincomplete-uni-patterns -Wmissing-deriving-strategies -Widentities -Wunused-packages -fplugin=Polysemy.Plugin
+  build-depends:
+      base >=4.12 && <5
+    , hasql ==1.6.*
+    , hedgehog ==1.1.*
+    , path ==0.9.*
+    , polysemy
+    , polysemy-db >=0.0.1.0 && <0.1
+    , polysemy-hasql >=0.0.1.0 && <0.1
+    , polysemy-plugin
+    , polysemy-test ==0.7.*
+    , prelate >=0.5.1 && <0.6
+    , sqel >=0.0.1 && <0.1
+    , uuid ==1.3.*
+  mixins:
+      base hiding (Prelude)
+    , prelate (Prelate as Prelude)
+    , prelate hiding (Prelate)
+  default-language: Haskell2010
+
+test-suite polysemy-hasql-test-unit
+  type: exitcode-stdio-1.0
+  main-is: Main.hs
+  other-modules:
+      Polysemy.Hasql.Test.MigrationTest
+  hs-source-dirs:
+      test
+  default-extensions:
+      StandaloneKindSignatures
+      AllowAmbiguousTypes
+      ApplicativeDo
+      BangPatterns
+      BinaryLiterals
+      BlockArguments
+      ConstraintKinds
+      DataKinds
+      DefaultSignatures
+      DeriveAnyClass
+      DeriveDataTypeable
+      DeriveFoldable
+      DeriveFunctor
+      DeriveGeneric
+      DeriveLift
+      DeriveTraversable
+      DerivingStrategies
+      DerivingVia
+      DisambiguateRecordFields
+      DoAndIfThenElse
+      DuplicateRecordFields
+      EmptyCase
+      EmptyDataDecls
+      ExistentialQuantification
+      FlexibleContexts
+      FlexibleInstances
+      FunctionalDependencies
+      GADTs
+      GeneralizedNewtypeDeriving
+      InstanceSigs
+      KindSignatures
+      LambdaCase
+      LiberalTypeSynonyms
+      MultiParamTypeClasses
+      MultiWayIf
+      NamedFieldPuns
+      OverloadedLabels
+      OverloadedLists
+      OverloadedStrings
+      PackageImports
+      PartialTypeSignatures
+      PatternGuards
+      PatternSynonyms
+      PolyKinds
+      QuantifiedConstraints
+      QuasiQuotes
+      RankNTypes
+      RecordWildCards
+      RecursiveDo
+      RoleAnnotations
+      ScopedTypeVariables
+      StandaloneDeriving
+      TemplateHaskell
+      TupleSections
+      TypeApplications
+      TypeFamilies
+      TypeFamilyDependencies
+      TypeOperators
+      TypeSynonymInstances
+      UndecidableInstances
+      UnicodeSyntax
+      ViewPatterns
+  ghc-options: -Wall -Wredundant-constraints -Wincomplete-uni-patterns -Wmissing-deriving-strategies -Widentities -Wunused-packages -fplugin=Polysemy.Plugin -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      aeson ==2.0.*
+    , base >=4.12 && <5
+    , chronos ==1.1.*
+    , exon ==1.4.*
+    , first-class-families ==0.8.*
+    , generics-sop ==0.5.*
+    , hasql ==1.6.*
+    , path ==0.9.*
+    , polysemy
+    , polysemy-db >=0.0.1.0 && <0.1
+    , polysemy-hasql >=0.0.1.0 && <0.1
+    , polysemy-hasql-test
+    , polysemy-plugin
+    , polysemy-test ==0.7.*
+    , prelate >=0.5.1 && <0.6
+    , sqel >=0.0.1 && <0.1
+    , tasty ==1.4.*
+  mixins:
+      base hiding (Prelude)
+    , prelate (Prelate as Prelude)
+    , prelate hiding (Prelate)
+  default-language: Haskell2010
diff --git a/test/Main.hs b/test/Main.hs
new file mode 100644
--- /dev/null
+++ b/test/Main.hs
@@ -0,0 +1,16 @@
+module Main where
+
+import Polysemy.Hasql.Test.MigrationTest (test_migrationConsistency, test_migrationErrors)
+import Polysemy.Test (unitTest)
+import Test.Tasty (TestTree, defaultMain, testGroup)
+
+tests :: TestTree
+tests =
+  testGroup "all" [
+    unitTest "migration errors" test_migrationErrors,
+    unitTest "migration consistency" test_migrationConsistency
+  ]
+
+main :: IO ()
+main =
+  defaultMain tests
diff --git a/test/Polysemy/Hasql/Test/MigrationTest.hs b/test/Polysemy/Hasql/Test/MigrationTest.hs
new file mode 100644
--- /dev/null
+++ b/test/Polysemy/Hasql/Test/MigrationTest.hs
@@ -0,0 +1,131 @@
+{-# options_ghc -Wno-partial-type-signatures #-}
+
+module Polysemy.Hasql.Test.MigrationTest where
+
+import Path (reldir)
+import qualified Polysemy.Test as Test
+import Polysemy.Test (UnitTest, assertJust, runTestAuto)
+import Prelude hiding (sum)
+import Sqel.Data.Dd (Dd, DdK (DdK), type (:>) ((:>)))
+import Sqel.Data.Migration (AutoMigrations, migrate)
+import Sqel.Data.Uid (Uid)
+import Sqel.Migration.Consistency (migrationConsistency)
+import Sqel.Migration.Table (migrateAuto)
+import Sqel.Names (typeAs)
+import Sqel.Prim (migrateDef, migrateDelete, migrateRename, prim, primNullable)
+import Sqel.Product (prod)
+import Sqel.Uid (uidAs)
+
+import Polysemy.Hasql.Test.Migration (testMigration)
+
+data PordOld =
+  PordOld {
+    p1 :: Int64
+  }
+  deriving stock (Eq, Show, Generic)
+
+data Pord =
+  Pord {
+    p1 :: Int64,
+    p2 :: Maybe Text
+  }
+  deriving stock (Eq, Show, Generic)
+
+data Dat0 =
+  Dat0 {
+    old :: Text
+  }
+  deriving stock (Eq, Show, Generic)
+
+data Dat1 =
+  Dat1 {
+    size :: Int64,
+    pord :: PordOld
+  }
+  deriving stock (Eq, Show, Generic)
+
+data Dat2 =
+  Dat2 {
+    number :: Int64,
+    pord :: Pord
+  }
+  deriving stock (Eq, Show, Generic)
+
+data Dat =
+  Dat {
+    name :: Text,
+    num :: Int64,
+    pord :: Pord
+  }
+  deriving stock (Eq, Show, Generic)
+
+data Q =
+  Q {
+    name :: Text
+  }
+  deriving stock (Eq, Show, Generic)
+
+t0 :: Dd ('DdK _ _ (Uid Int64 Dat0) _)
+t0 =
+  uidAs @"dat" prim (prod (migrateDelete prim))
+
+t1 :: Dd ('DdK _ _ (Uid Int64 Dat1) _)
+t1 =
+  uidAs @"dat" prim (prod (
+    migrateDelete (migrateDef 0 prim) :>
+    typeAs @"Pord" (prod (
+      migrateDef 53 prim
+    ))
+  ))
+
+t2 :: Dd ('DdK _ _ (Uid Int64 Dat2) _)
+t2 =
+  uidAs @"dat" prim (prod (
+    migrateDef 15 prim :>
+    typeAs @"Pord" (prod (
+      prim :>
+      primNullable
+    ))
+  ))
+
+tcur :: Dd ('DdK _ _ (Uid Int64 Dat) _)
+tcur =
+  uidAs @"dat" prim (prod (
+    migrateDef ("vunqach" :: Text) prim :>
+    migrateRename @"number" prim :>
+    prod (
+      prim :>
+      primNullable
+    )
+  ))
+
+migrations ::
+  AutoMigrations (Sem r) [Uid Int64 Dat2, Uid Int64 Dat1, Uid Int64 Dat0] (Uid Int64 Dat)
+migrations =
+  migrate (
+    migrateAuto t2 tcur :>
+    migrateAuto t1 t2 :>
+    migrateAuto t0 t1
+  )
+
+migrationErrors :: NonEmpty Text
+migrationErrors =
+  [
+    "The migration table 'dat' has mismatched columns:",
+    " • The column 'number' with type 'bigint' was removed.",
+    "The composite type 'sqel_type__pord' has mismatched columns:",
+    " • The type of the column 'p1' was changed from 'text' to 'bigint'.",
+    "The type 'sqel_type__point' was removed."
+  ]
+
+test_migrationErrors :: UnitTest
+test_migrationErrors =
+  runTestAuto do
+    fixtures <- Test.fixturePath [reldir|migration-error|]
+    assertJust migrationErrors =<< migrationConsistency fixtures migrations False
+
+-- TODO error message claims type change if a column constraint differs
+test_migrationConsistency :: UnitTest
+test_migrationConsistency =
+  runTestAuto do
+    testMigration migrations False