Capture stdout/stderr during tests and display it for failures

libexec/bats-exec

@@ -29,11 +29,6 @@ run() {
   [ -z "$e" ] || set -e
 }
 
-abort() {
-  [ "$#" -eq 0 ] || echo error: "$@" >&2
-  exit 1
-}
-
 setup() {
   true
 }
@@ -54,19 +49,25 @@ bats_test_function() {
 
 bats_teardown_trap() {
   trap bats_exit_trap err exit
-  teardown
+  teardown >>"$BATS_OUT" 2>&1
   bats_exit_trap
 }
 
 bats_exit_trap() {
+  local status
   trap - err exit
+
   if [ -z "$BATS_TEST_COMPLETED" ]; then
-    echo "not ok $BATS_TEST_NUMBER $BATS_TEST_DESCRIPTION"
-    exit 1
+    echo "not ok $BATS_TEST_NUMBER $BATS_TEST_DESCRIPTION" >&3
+    sed -e "s/^/    /" < "$BATS_OUT" >&3
+    status=1
   else
-    echo "ok $BATS_TEST_NUMBER $BATS_TEST_DESCRIPTION"
-    exit 0
+    echo "ok $BATS_TEST_NUMBER $BATS_TEST_DESCRIPTION" >&3
+    status=0
   fi
+
+  rm -f "$BATS_OUT"
+  exit "$status"
 }
 
 bats_perform_tests() {
@@ -91,8 +92,9 @@ bats_perform_test() {
 
     BATS_TEST_COMPLETED=""
     trap bats_teardown_trap err exit
-    setup
-    "$BATS_TEST_NAME"
+    { setup
+      "$BATS_TEST_NAME"
+    } >>"$BATS_OUT" 2>&1
     BATS_TEST_COMPLETED=1
 
   else
@@ -101,6 +103,15 @@ bats_perform_test() {
   fi
 }
 
+if [ -z "$TMPDIR" ]; then
+  BATS_TMPDIR="/tmp"
+else
+  BATS_TMPDIR="${TMPDIR%/}"
+fi
+BATS_OUT="$BATS_TMPDIR/bats.$(date "+%Y%m%d%H%M%S").$$"
+
+exec 3<&1
+
 eval "$(bats-preprocess < "$BATS_TEST_FILENAME")"
 
 if [ "$#" -eq 0 ]; then

test/bats.bats

@@ -72,3 +72,11 @@ teardown() {
   run bats "$FIXTURE_ROOT/load.bats"
   [ $status -eq 0 ]
 }
+
+@test "output is discarded for passing tests and printed for failing tests" {
+  run bats "$FIXTURE_ROOT/output.bats"
+  [ $status -eq 1 ]
+  [ "${lines[4]}" = "    failure stdout 1" ]
+  [ "${lines[5]}" = "    failure stdout 2" ]
+  [ "${lines[7]}" = "    failure stderr" ]
+}

test/fixtures/output.bats

@@ -0,0 +1,19 @@
+@test "success writing to stdout" {
+  echo "success stdout 1"
+  echo "success stdout 2"
+}
+
+@test "success writing to stderr" {
+  echo "success stderr" >&2
+}
+
+@test "failure writing to stdout" {
+  echo "failure stdout 1"
+  echo "failure stdout 2"
+  false
+}
+
+@test "failure writing to stderr" {
+  echo "failure stderr" >&2
+  false
+}