Fix windows build

- findExecutable sh
- Use single quotes for cabal exec

Author: phadej

cabal-install/tests/IntegrationTests.hs

@@ -27,6 +27,7 @@ import Control.Concurrent.Async (withAsync, wait)
 import Control.Exception (bracket)
 import System.Directory
         ( canonicalizePath
+        , findExecutable
         , getDirectoryContents
         , getTemporaryDirectory
         , doesDirectoryExist
@@ -195,7 +196,8 @@ runTestCase assertResult tc = do
   bracket createWorkDirectory (removeWorkDirectory doRemove) $ \workDirectory -> do
     -- Run
     let scriptDirectory = workDirectory </> tcShouldX tc
-    testResult <- run scriptDirectory "/bin/sh" [ "-e", tcName tc]
+    Just sh <- findExecutable "sh"
+    testResult <- run scriptDirectory sh [ "-e", tcName tc]
     -- Assert that we got what we expected
     assertResult testResult
     mustMatch testResult "stdout" (trStdOut testResult) (tcStdOutPath tc)

cabal-install/tests/IntegrationTests/exec/should_run/configures_cabal_to_use_sandbox.sh

@@ -11,4 +11,4 @@ $GHC_PKG list | grep -v "my-0.1"
 
 # When run inside 'cabal-exec' the 'sandbox hc-pkg list' sub-command
 # should find the library.
-cabal exec sh -- -c "cd subdir && $CABAL sandbox hc-pkg list" | grep "my-0.1"
+cabal exec sh -- -c 'cd subdir && $CABAL sandbox hc-pkg list' | grep "my-0.1"