diff --git a/test/build.bats b/test/build.bats
index a3c65e84..4cc0130f 100644
--- a/test/build.bats
+++ b/test/build.bats
@@ -546,7 +546,7 @@ install_package "jruby-9000.dev" "http://lafo.ssw.uni-linz.ac.at/jruby-9000+graa
 DEF
   assert_success
 
-  assert [ ! -e "$INSTALL_ROOT/build.log" ]
+  refute [ -e "$INSTALL_ROOT/build.log" ]
 }
 
 @test "JRuby Java 7 missing" {
diff --git a/test/cache.bats b/test/cache.bats
index e2dc9662..998f1637 100644
--- a/test/cache.bats
+++ b/test/cache.bats
@@ -83,7 +83,7 @@ setup() {
 
   assert_success
   assert [ -x "${INSTALL_ROOT}/bin/package" ]
-  assert [ ! -d "$RUBY_BUILD_CACHE_PATH" ]
+  refute [ -d "$RUBY_BUILD_CACHE_PATH" ]
 
   unstub curl
 }
diff --git a/test/checksum.bats b/test/checksum.bats
index ba8ea2b9..d3130f6a 100644
--- a/test/checksum.bats
+++ b/test/checksum.bats
@@ -38,7 +38,7 @@ export RUBY_BUILD_CACHE_PATH=
   install_fixture definitions/with-invalid-checksum
 
   assert_failure
-  assert [ ! -f "${INSTALL_ROOT}/bin/package" ]
+  refute [ -f "${INSTALL_ROOT}/bin/package" ]
 
   unstub curl
   unstub shasum
@@ -94,7 +94,7 @@ export RUBY_BUILD_CACHE_PATH=
   install_fixture definitions/with-checksum
 
   assert_failure
-  assert [ ! -f "${INSTALL_ROOT}/bin/package" ]
+  refute [ -f "${INSTALL_ROOT}/bin/package" ]
 
   unstub curl
   unstub shasum
@@ -151,7 +151,7 @@ install_package "package-1.0.0" "http://example.com/packages/package-1.0.0.tar.g
 DEF
 
   assert_failure
-  assert [ ! -f "${INSTALL_ROOT}/bin/package" ]
+  refute [ -f "${INSTALL_ROOT}/bin/package" ]
   assert_output_contains "unexpected checksum length: 29 (checksum_of_unexpected_length)"
   assert_output_contains "expected 0 (no checksum), 32 (MD5), or 64 (SHA2-256)"
 }
diff --git a/test/definitions.bats b/test/definitions.bats
index 3f57ded9..e1eab421 100644
--- a/test/definitions.bats
+++ b/test/definitions.bats
@@ -13,7 +13,7 @@ NUM_DEFINITIONS="$(ls "$BATS_TEST_DIRNAME"/../share/ruby-build | wc -l)"
 
 @test "custom RUBY_BUILD_ROOT: nonexistent" {
   export RUBY_BUILD_ROOT="$TMP"
-  assert [ ! -e "${RUBY_BUILD_ROOT}/share/ruby-build" ]
+  refute [ -e "${RUBY_BUILD_ROOT}/share/ruby-build" ]
   run ruby-build --definitions
   assert_success ""
 }
diff --git a/test/hooks.bats b/test/hooks.bats
index a09f189d..fa6f9951 100644
--- a/test/hooks.bats
+++ b/test/hooks.bats
@@ -52,5 +52,5 @@ rehashed
 after.
 OUT
 
-  assert [ ! -d "${RBENV_ROOT}/versions/2.0.0" ]
+  refute [ -d "${RBENV_ROOT}/versions/2.0.0" ]
 }
diff --git a/test/rbenv.bats b/test/rbenv.bats
index 7dfc17c6..2d8c95ff 100644
--- a/test/rbenv.bats
+++ b/test/rbenv.bats
@@ -97,7 +97,7 @@ OUT
 }
 
 @test "no build definitions from plugins" {
-  assert [ ! -e "${RBENV_ROOT}/plugins" ]
+  refute [ -e "${RBENV_ROOT}/plugins" ]
   stub_ruby_build 'echo $RUBY_BUILD_DEFINITIONS'
 
   run rbenv-install 2.1.2
diff --git a/test/test_helper.bash b/test/test_helper.bash
index baac740f..b61331c2 100644
--- a/test/test_helper.bash
+++ b/test/test_helper.bash
@@ -71,6 +71,12 @@ assert() {
   fi
 }
 
+refute() {
+  if "$@"; then
+    flunk "expected to fail: $@"
+  fi
+}
+
 flunk() {
   { if [ "$#" -eq 0 ]; then cat -
     else echo "$@"