diff --git a/test/lib/test-lib.sh b/test/lib/test-lib.sh
index fce00583b..c8437ff47 100644
--- a/test/lib/test-lib.sh
+++ b/test/lib/test-lib.sh
@@ -29,6 +29,7 @@ SHARNESS_LIB="lib/sharness/sharness.sh"
 # Please put go-ipfs specific shell functions below
 
 test "$TEST_NO_FUSE" != 1 && test_set_prereq FUSE
+test "$TEST_EXPENSIVE" = 1 && test_set_prereq EXPENSIVE
 
 test_cmp_repeat_10_sec() {
 	for i in 1 2 3 4 5 6 7 8 9 10
diff --git a/test/t0040-add-and-cat.sh b/test/t0040-add-and-cat.sh
index 1be996861..cf5fbfc39 100755
--- a/test/t0040-add-and-cat.sh
+++ b/test/t0040-add-and-cat.sh
@@ -42,47 +42,45 @@ test_expect_success "go-random is installed" '
 	type random
 '
 
-test_expect_success "generate 100MB file using go-random" '
+test_expect_success EXPENSIVE "generate 100MB file using go-random" '
 	random 104857600 42 >mountdir/bigfile
 '
 
-test_expect_success "sha1 of the file looks ok" '
+test_expect_success EXPENSIVE "sha1 of the file looks ok" '
 	echo "885b197b01e0f7ff584458dc236cb9477d2e736d  mountdir/bigfile" >sha1_expected &&
 	shasum mountdir/bigfile >sha1_actual &&
 	test_cmp sha1_expected sha1_actual
 '
 
-test_expect_success "ipfs add bigfile succeeds" '
+test_expect_success EXPENSIVE "ipfs add bigfile succeeds" '
 	ipfs add mountdir/bigfile >actual
 '
 
-test_expect_success "ipfs add bigfile output looks good" '
+test_expect_success EXPENSIVE "ipfs add bigfile output looks good" '
 	HASH="QmWXysX1oysyjTqd5xGM2T1maBaVXnk5svQv4GKo5PsGPo" &&
 	echo "added $HASH mountdir/bigfile" >expected &&
 	test_cmp expected actual
 '
 
-test_expect_success "ipfs cat succeeds" '
+test_expect_success EXPENSIVE "ipfs cat succeeds" '
 	ipfs cat $HASH | shasum >sha1_actual
 '
 
-# this test commented out to run faster.
-# uncomment to produce and examine output
-# test_expect_success "ipfs cat output looks good" '
-#   ipfs cat $HASH >actual &&
-# 	test_cmp mountdir/bigfile actual
-# '
+test_expect_success EXPENSIVE "ipfs cat output looks good" '
+	ipfs cat $HASH >actual &&
+	test_cmp mountdir/bigfile actual
+'
 
-test_expect_success "ipfs cat output shasum looks good" '
+test_expect_success EXPENSIVE "ipfs cat output shasum looks good" '
 	echo "885b197b01e0f7ff584458dc236cb9477d2e736d  -" >sha1_expected &&
 	test_cmp sha1_expected sha1_actual
 '
 
-test_expect_success FUSE "cat ipfs/bigfile succeeds" '
+test_expect_success FUSE,EXPENSIVE "cat ipfs/bigfile succeeds" '
 	cat ipfs/$HASH | shasum >sha1_actual
 '
 
-test_expect_success FUSE "cat ipfs/bigfile looks good" '
+test_expect_success FUSE,EXPENSIVE "cat ipfs/bigfile looks good" '
 	test_cmp sha1_expected sha1_actual
 '