Use simpler version check in test suite

postgresql-simple-interval.cabal

@@ -28,7 +28,6 @@ common library
     base >=4.13 && <4.22,
     bytestring >=0.10.10 && <0.13,
     postgresql-simple ^>=0.7,
-    text >=1.2.4 && <1.3 || >=2.0 && <2.2,
 
   default-language: Haskell2010
   ghc-options:
@@ -64,6 +63,7 @@ library
   build-depends:
     persistent ^>=2.17,
     scientific ^>=0.3.8,
+    text >=1.2.4 && <1.3 || >=2.0 && <2.2,
 
   -- cabal-gild: discover source/library
   exposed-modules:
@@ -74,7 +74,10 @@ library
 
 test-suite postgresql-simple-interval-test-suite
   import: executable
-  build-depends: hspec ^>=2.11.12
+  build-depends:
+    hspec ^>=2.11.12,
+    postgresql-libpq ^>=0.11,
+
   hs-source-dirs: source/test-suite
   main-is: Main.hs
   type: exitcode-stdio-1.0

source/test-suite/Main.hs

@@ -8,12 +8,12 @@ import qualified Data.ByteString as ByteString
 import qualified Data.ByteString.Builder as Builder
 import qualified Data.ByteString.Lazy as LazyByteString
 import qualified Data.Int as Int
-import qualified Data.Text as Text
+import qualified Database.PostgreSQL.LibPQ as Pq
 import qualified Database.PostgreSQL.Simple as Postgres
+import qualified Database.PostgreSQL.Simple.Internal as Postgres
 import qualified Database.PostgreSQL.Simple.Interval.Unstable as I
 import qualified Database.PostgreSQL.Simple.ToField as Postgres
 import qualified Test.Hspec as H
-import qualified Text.Read as Read
 
 main :: IO ()
 main = H.hspec spec
@@ -165,14 +165,10 @@ spec = H.describe "Database.PostgreSQL.Simple.Interval" $ do
               case result of
                 Right actual -> actual `H.shouldBe` [Postgres.Only interval]
                 Left somePostgresqlException -> do
-                  rows <- Postgres.query_ connection "select version()"
-                  case rows of
-                    Postgres.Only text : _
-                      | _ : rawVersion : _ <- Text.words text,
-                        Just version <- Read.readMaybe (Text.unpack rawVersion),
-                        version < (15 :: Double) ->
-                          H.pendingWith $ "interval parsing broken with PostgreSQL version " <> show version
-                    _ -> Exception.throwIO (somePostgresqlException :: Postgres.SomePostgreSqlException)
+                  version <- Postgres.withConnection connection Pq.serverVersion
+                  if version < 150000
+                    then H.pendingWith $ "interval parsing broken with PostgreSQL version " <> show version
+                    else Exception.throwIO (somePostgresqlException :: Postgres.SomePostgreSqlException)
 
 data IntervalStyle
   = Iso8601