Fix race condition in the language tests

When we pipe to `>(...)` like that, we unfortunately don't wait for the
process to finish. Better to just substitute the file.

Also, use the "unified" diff output that people (including myself) are
more familiar with, thanks to Git.

1 files changed, 3 insertions, 2 deletions

diff --git a/tests/lang.sh b/tests/lang.sh
index bfb942d3d..75dbbc38e 100755
--- a/tests/lang.sh
+++ b/tests/lang.sh
@@ -52,9 +52,10 @@ for i in lang/parse-okay-*.nix; do
     i=$(basename "$i" .nix)
     if
         expect 0 nix-instantiate --parse - < "lang/$i.nix" \
-            1> >(sed "s!$(pwd)!/pwd!g" > "lang/$i.out") \
-            2> >(sed "s!$(pwd)!/pwd!g" > "lang/$i.err")
+            1> "lang/$i.out" \
+            2> "lang/$i.err"
     then
+        sed "s!$(pwd)!/pwd!g" "lang/$i.out" "lang/$i.err"
         diffAndAccept "$i" out exp
         diffAndAccept "$i" err err.exp
     else