testsuite: Ensure that ffi005 output order is predictable

The libc output buffer wasn't being flushed, making the order
system-depedent.

4 files changed, 14 insertions, 6 deletions

diff --git a/testsuite/tests/ffi/should_run/all.T b/testsuite/tests/ffi/should_run/all.T
index fa78c56b80..1a85e8ac66 100644
--- a/testsuite/tests/ffi/should_run/all.T
+++ b/testsuite/tests/ffi/should_run/all.T
@@ -28,11 +28,11 @@ test('ffi004', skip, compile_and_run, [''])
 # On x86, the test suffers from floating-point differences due to the
 # use of 80-bit internal precision when using the native code generator.
 #
-test('ffi005', [ omit_ways(prof_ways),
+test('ffi005', [ omit_ways(prof_ways + ['ghci']),
                  when(arch('i386'), skip),
                  when(platform('i386-apple-darwin'), expect_broken(4105)),
                  exit_code(3) ],
-               compile_and_run, [''])
+               compile_and_run, ['ffi005_c.c'])
 
 test('ffi006', normal, compile_and_run, [''])
 
diff --git a/testsuite/tests/ffi/should_run/ffi005.hs b/testsuite/tests/ffi/should_run/ffi005.hs
index 9c17441954..85437a422f 100644
--- a/testsuite/tests/ffi/should_run/ffi005.hs
+++ b/testsuite/tests/ffi/should_run/ffi005.hs
@@ -20,10 +20,12 @@ main = do
 --  putStrLn $ "errno == " ++ show err
 
   putStrLn "\nTesting puts (and withString)"
-  withCString "Test successful" puts
+  hFlush stdout
+  withCString "Test puts successful" puts
+  flushStdout  -- Flush the libc output buffer
 
   putStrLn "\nTesting peekArray0"
-  s <- withCString "Test successful" (peekArray0 (castCharToCChar '\0'))
+  s <- withCString "Test peekArray0 successful" (peekArray0 (castCharToCChar '\0'))
   putStr (map castCCharToChar s)
 
 -- disabled due to use of non-portable constants in arguments to open:
@@ -71,6 +73,7 @@ withBuffer sz m = do
   return s
 
 foreign import ccall puts :: CString -> IO CInt
+foreign import ccall "flush_stdout" flushStdout :: IO ()
 
 -- foreign import ccall "open" open'  :: CString -> CInt -> IO CInt
 -- foreign import ccall "open" open2' :: CString -> CInt -> CInt -> IO CInt
diff --git a/testsuite/tests/ffi/should_run/ffi005.stdout b/testsuite/tests/ffi/should_run/ffi005.stdout
index bc0a137514..bc29221ccf 100644
--- a/testsuite/tests/ffi/should_run/ffi005.stdout
+++ b/testsuite/tests/ffi/should_run/ffi005.stdout
@@ -3,9 +3,10 @@ Testing sin==mysin (should return lots of Trues)
 [True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True]
 
 Testing puts (and withString)
+Test puts successful
 
 Testing peekArray0
-Test successful
+Test peekArray0 successful
 Testing sin==dynamic_sin (should return lots of Trues)
 [True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True]
 
@@ -16,4 +17,3 @@ Testing sin==Id wrapped_sin (should return lots of Trues)
 [True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True,True]
 
 Testing exit
-Test successful
diff --git a/testsuite/tests/ffi/should_run/ffi005_c.c b/testsuite/tests/ffi/should_run/ffi005_c.c
new file mode 100644
index 0000000000..e5a88e1b4e
--- /dev/null
+++ b/testsuite/tests/ffi/should_run/ffi005_c.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+void flush_stdout(void)
+{
+    fflush(stdout);
+}