diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,24 @@
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to the [Haskell Package Versioning Policy](https://pvp.haskell.org/).
 
+## 0.2.1.3 – 2024–03–11
+
+### Added
+
+- The tests for `yaya` were previously in their own `yaya-test` package, but that has been folded into this package. Ideally, the tests would live in the `yaya` package, but Cabal doesn’t play well with circular dependencies between packages (even if the component dependencies aren’t circular).
+
+## 0.2.1.2
+
+Unknown changes.
+
+## 0.2.1.1
+
+Unknown changes.
+
+## 0.2.1.0
+
+Unknown changes.
+
 ## 0.2.0.2 – 2023–12–21
 
 ### Changed
diff --git a/tests/Test/Fold.hs b/tests/Test/Fold.hs
new file mode 100644
--- /dev/null
+++ b/tests/Test/Fold.hs
@@ -0,0 +1,42 @@
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE Unsafe #-}
+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
+
+module Test.Fold (tests) where
+
+import safe "base" Control.Category (Category (id))
+import safe "base" Control.Monad ((=<<))
+import safe "base" Data.Bool (Bool)
+import safe "base" Data.Function (($))
+import safe "base" Data.Proxy (Proxy (Proxy))
+import safe "base" System.IO (IO)
+import safe "hedgehog" Hedgehog (Property, checkParallel, discover, forAll, property)
+import safe qualified "hedgehog" Hedgehog.Gen as Gen
+import safe "yaya" Yaya.Fold (Mu)
+import safe "yaya" Yaya.Fold.Common (size)
+import safe "yaya-hedgehog" Yaya.Hedgehog.Expr (Expr, genExpr, genMuExpr)
+import safe "yaya-hedgehog" Yaya.Hedgehog.Fold
+  ( law_cataCancel,
+    law_cataCompose,
+    law_cataRefl,
+  )
+
+-- TODO: For some reason HLint is complaining that TemplateHaskell is unused.
+{-# HLINT ignore "Unused LANGUAGE pragma" #-}
+
+prop_muCataCancel :: Property
+prop_muCataCancel =
+  property $ law_cataCancel size =<< forAll (genExpr (Gen.sized genMuExpr))
+
+prop_muCataRefl :: Property
+prop_muCataRefl =
+  property $ law_cataRefl =<< forAll (Gen.sized genMuExpr)
+
+prop_muCataCompose :: Property
+prop_muCataCompose =
+  property $
+    law_cataCompose (Proxy :: Proxy (Mu Expr)) size id
+      =<< forAll (Gen.sized genMuExpr)
+
+tests :: IO Bool
+tests = checkParallel $$discover
diff --git a/tests/Test/Fold/Common.hs b/tests/Test/Fold/Common.hs
new file mode 100644
--- /dev/null
+++ b/tests/Test/Fold/Common.hs
@@ -0,0 +1,39 @@
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE Unsafe #-}
+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
+
+module Test.Fold.Common (tests) where
+
+import safe "base" Control.Category (Category ((.)))
+import safe "base" Control.Monad ((=<<))
+import safe "base" Data.Bool (Bool)
+import safe "base" Data.Functor (Functor (fmap))
+import safe "base" Data.Ord (Ord ((<)))
+import safe "base" System.IO (IO)
+import safe "hedgehog" Hedgehog
+  ( Property,
+    assert,
+    checkParallel,
+    discover,
+    forAll,
+    property,
+  )
+import safe qualified "hedgehog" Hedgehog.Gen as Gen
+import safe "yaya" Yaya.Fold (Recursive (cata), zipAlgebras)
+import safe "yaya" Yaya.Fold.Common (height, size)
+import safe "yaya" Yaya.Pattern (uncurry)
+import safe "yaya-hedgehog" Yaya.Hedgehog.Expr (genMuExpr)
+import safe "base" Prelude (Integral (toInteger))
+
+-- TODO: For some reason HLint is complaining that TemplateHaskell is unused.
+{-# HLINT ignore "Unused LANGUAGE pragma" #-}
+
+prop_heightLtSize :: Property
+prop_heightLtSize =
+  property
+    ( assert . uncurry (<) . fmap toInteger . cata (zipAlgebras height size)
+        =<< forAll (Gen.sized genMuExpr)
+    )
+
+tests :: IO Bool
+tests = checkParallel $$discover
diff --git a/tests/Test/Fold/Native.hs b/tests/Test/Fold/Native.hs
new file mode 100644
--- /dev/null
+++ b/tests/Test/Fold/Native.hs
@@ -0,0 +1,42 @@
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE Unsafe #-}
+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
+
+module Test.Fold.Native (tests) where
+
+import safe "base" Control.Category (Category (id))
+import safe "base" Control.Monad ((=<<))
+import safe "base" Data.Bool (Bool)
+import safe "base" Data.Function (($))
+import safe "base" Data.Proxy (Proxy (Proxy))
+import safe "base" System.IO (IO)
+import safe "hedgehog" Hedgehog (Property, checkParallel, discover, forAll, property)
+import safe qualified "hedgehog" Hedgehog.Gen as Gen
+import safe "yaya" Yaya.Fold.Common (size)
+import safe "yaya" Yaya.Fold.Native (Fix)
+import safe "yaya-hedgehog" Yaya.Hedgehog.Expr (Expr, genExpr, genFixExpr)
+import safe "yaya-hedgehog" Yaya.Hedgehog.Fold
+  ( law_cataCancel,
+    law_cataCompose,
+    law_cataRefl,
+  )
+
+-- TODO: For some reason HLint is complaining that TemplateHaskell is unused.
+{-# HLINT ignore "Unused LANGUAGE pragma" #-}
+
+prop_fixCataCancel :: Property
+prop_fixCataCancel =
+  property $ law_cataCancel size =<< forAll (genExpr (Gen.sized genFixExpr))
+
+prop_fixCataRefl :: Property
+prop_fixCataRefl =
+  property $ law_cataRefl =<< forAll (Gen.sized genFixExpr)
+
+prop_fixCataCompose :: Property
+prop_fixCataCompose =
+  property $
+    law_cataCompose (Proxy :: Proxy (Fix Expr)) size id
+      =<< forAll (Gen.sized genFixExpr)
+
+tests :: IO Bool
+tests = checkParallel $$discover
diff --git a/tests/Test/Retrofit.hs b/tests/Test/Retrofit.hs
new file mode 100644
--- /dev/null
+++ b/tests/Test/Retrofit.hs
@@ -0,0 +1,35 @@
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE Unsafe #-}
+
+-- | The point of this module is that it should compile _without_ importing any
+--   other Yaya modules.
+module Test.Retrofit (tests) where
+
+import safe "base" Data.Bool (Bool)
+import safe "base" Data.Eq (Eq)
+import safe "base" Data.Int (Int)
+import safe "base" System.IO (IO)
+import safe "base" Text.Show (Show)
+import safe "hedgehog" Hedgehog (checkParallel, discover)
+import safe "yaya" Yaya.Retrofit (defaultRules, extractPatternFunctor)
+
+data DExpr
+  = Lit Int
+  | Add DExpr DExpr
+  | Mult DExpr DExpr
+  deriving stock (Eq, Show)
+
+extractPatternFunctor defaultRules ''DExpr
+
+-- -- | This can be derived in this case, but we want to ensure we could define it
+-- --   if necessary.
+-- instance Eq DExpr where
+--   (==) = recursiveEq
+
+-- -- | This can be derived in this case, but we want to ensure we could define it
+-- --   if necessary.
+-- instance Show DExpr where
+--   showsPrec = recursiveShowsPrec
+
+tests :: IO Bool
+tests = checkParallel $$discover
diff --git a/tests/test.hs b/tests/test.hs
new file mode 100644
--- /dev/null
+++ b/tests/test.hs
@@ -0,0 +1,10 @@
+{-# LANGUAGE Unsafe #-}
+
+import safe "base" System.IO (IO)
+import safe "hedgehog" Hedgehog.Main (defaultMain)
+import qualified "this" Test.Fold as Fold
+import qualified "this" Test.Fold.Common as Fold.Common
+import qualified "this" Test.Retrofit as Retrofit
+
+main :: IO ()
+main = defaultMain [Fold.tests, Fold.Common.tests, Retrofit.tests]
diff --git a/yaya-hedgehog.cabal b/yaya-hedgehog.cabal
--- a/yaya-hedgehog.cabal
+++ b/yaya-hedgehog.cabal
@@ -1,7 +1,7 @@
 cabal-version:  3.0
 
 name:        yaya-hedgehog
-version:     0.2.1.2
+version:     0.2.1.3
 synopsis:    Hedgehog testing support for the Yaya recursion scheme
              library.
 description: If you use Yaya in your own code and have tests written
@@ -204,3 +204,44 @@
     -- “Build_doctests.hs”, we set it here, and that means it has to match
     -- doctests.hs, which is `Unsafe`.
     Unsafe
+
+-- NB: This suite should be in the `yaya` package, but it can’t because it
+--     depends on `yaya-hedgehog`.
+test-suite yaya
+  import: defaults
+  type: exitcode-stdio-1.0
+  hs-source-dirs:
+    tests
+  main-is: test.hs
+  other-modules:
+    Test.Fold
+    Test.Fold.Common
+    Test.Fold.Native
+    Test.Retrofit
+  build-depends:
+    deriving-compat,
+    hedgehog,
+    yaya >= 0.5.0,
+    yaya-hedgehog >= 0.2.0,
+  ghc-options:
+    -rtsopts
+    -threaded
+    -trust adjunctions
+    -trust array
+    -trust base-orphans
+    -trust binary
+    -trust bytestring
+    -trust containers
+    -trust distributive
+    -trust exceptions
+    -trust ghc-prim
+    -trust hashable
+    -trust profunctors
+    -trust semigroupoids
+    -trust stm
+    -trust text
+    -trust transformers-compat
+    -with-rtsopts=-N
+  if impl(ghc < 9.6)
+    ghc-options:
+      -trust foldable1-classes-compat