52 files changed, 60 insertions, 143 deletions

diff --git a/test/lld/duplicate_imports.wast.out b/test/lld/duplicate_imports.wast.out
index cbb1db44a..b8d046ab7 100644
--- a/test/lld/duplicate_imports.wast.out
+++ b/test/lld/duplicate_imports.wast.out
@@ -138,13 +138,6 @@
     "invoke_ffd"
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/em_asm.wast.mem.out b/test/lld/em_asm.wast.mem.out
index 13484ff3d..2aac1ef36 100644
--- a/test/lld/em_asm.wast.mem.out
+++ b/test/lld/em_asm.wast.mem.out
@@ -262,13 +262,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/em_asm.wast.out b/test/lld/em_asm.wast.out
index 7986466cd..5917fb187 100644
--- a/test/lld/em_asm.wast.out
+++ b/test/lld/em_asm.wast.out
@@ -263,13 +263,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/em_asm_O0.wast.out b/test/lld/em_asm_O0.wast.out
index 45868e567..d194c8185 100644
--- a/test/lld/em_asm_O0.wast.out
+++ b/test/lld/em_asm_O0.wast.out
@@ -123,13 +123,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/em_asm_shared.wast.out b/test/lld/em_asm_shared.wast.out
index 19eabedc8..220a10aca 100644
--- a/test/lld/em_asm_shared.wast.out
+++ b/test/lld/em_asm_shared.wast.out
@@ -255,13 +255,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/em_asm_table.wast.out b/test/lld/em_asm_table.wast.out
index 1ed2cd5bd..50f24876e 100644
--- a/test/lld/em_asm_table.wast.out
+++ b/test/lld/em_asm_table.wast.out
@@ -93,13 +93,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/em_js_O0.wast.out b/test/lld/em_js_O0.wast.out
index 3db4c83d7..02d4fed07 100644
--- a/test/lld/em_js_O0.wast.out
+++ b/test/lld/em_js_O0.wast.out
@@ -73,13 +73,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/hello_world.wast.mem.out b/test/lld/hello_world.wast.mem.out
index 79ef1342a..834f4945a 100644
--- a/test/lld/hello_world.wast.mem.out
+++ b/test/lld/hello_world.wast.mem.out
@@ -98,13 +98,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/hello_world.wast.out b/test/lld/hello_world.wast.out
index c4a54667b..67fd6428b 100644
--- a/test/lld/hello_world.wast.out
+++ b/test/lld/hello_world.wast.out
@@ -99,13 +99,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/init.wast.out b/test/lld/init.wast.out
index 676f00327..645f78f67 100644
--- a/test/lld/init.wast.out
+++ b/test/lld/init.wast.out
@@ -110,13 +110,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/recursive.wast.out b/test/lld/recursive.wast.out
index 277d3cf1f..8f81cdc91 100644
--- a/test/lld/recursive.wast.out
+++ b/test/lld/recursive.wast.out
@@ -156,13 +156,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/reserved_func_ptr.wast.out b/test/lld/reserved_func_ptr.wast.out
index 5a5a6f29d..3ddf2f0ce 100644
--- a/test/lld/reserved_func_ptr.wast.out
+++ b/test/lld/reserved_func_ptr.wast.out
@@ -193,13 +193,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/lld/shared.wast.out b/test/lld/shared.wast.out
index 7716daa32..135aa3e5b 100644
--- a/test/lld/shared.wast.out
+++ b/test/lld/shared.wast.out
@@ -124,13 +124,6 @@
   "invokeFuncs": [
   ],
   "features": [
-    "--mvp-features",
-    "--enable-threads",
-    "--enable-bulk-memory",
-    "--enable-mutable-globals",
-    "--enable-nontrapping-float-to-int",
-    "--enable-sign-ext",
-    "--enable-simd"
   ]
 }
 -- END METADATA --
diff --git a/test/passes/code-folding.txt b/test/passes/code-folding_enable-threads.txt
index 0fe3aa144..0fe3aa144 100644
--- a/test/passes/code-folding.txt
+++ b/test/passes/code-folding_enable-threads.txt
diff --git a/test/passes/code-folding.wast b/test/passes/code-folding_enable-threads.wast
index d9c1cc950..d9c1cc950 100644
--- a/test/passes/code-folding.wast
+++ b/test/passes/code-folding_enable-threads.wast
diff --git a/test/passes/flatten_dfo_O3.txt b/test/passes/flatten_dfo_O3_enable-threads.txt
index 74ddb5e2e..74ddb5e2e 100644
--- a/test/passes/flatten_dfo_O3.txt
+++ b/test/passes/flatten_dfo_O3_enable-threads.txt
diff --git a/test/passes/flatten_dfo_O3.wast b/test/passes/flatten_dfo_O3_enable-threads.wast
index e6e136b68..e6e136b68 100644
--- a/test/passes/flatten_dfo_O3.wast
+++ b/test/passes/flatten_dfo_O3_enable-threads.wast
diff --git a/test/passes/flatten_simplify-locals-nonesting_souperify-single-use.txt b/test/passes/flatten_simplify-locals-nonesting_souperify-single-use_enable-threads.txt
index af2ba0f59..af2ba0f59 100644
--- a/test/passes/flatten_simplify-locals-nonesting_souperify-single-use.txt
+++ b/test/passes/flatten_simplify-locals-nonesting_souperify-single-use_enable-threads.txt
diff --git a/test/passes/flatten_simplify-locals-nonesting_souperify-single-use.wast b/test/passes/flatten_simplify-locals-nonesting_souperify-single-use_enable-threads.wast
index cfb94aa5c..cfb94aa5c 100644
--- a/test/passes/flatten_simplify-locals-nonesting_souperify-single-use.wast
+++ b/test/passes/flatten_simplify-locals-nonesting_souperify-single-use_enable-threads.wast
diff --git a/test/passes/flatten_simplify-locals-nonesting_souperify.txt b/test/passes/flatten_simplify-locals-nonesting_souperify_enable-threads.txt
index 6d70acdcd..6d70acdcd 100644
--- a/test/passes/flatten_simplify-locals-nonesting_souperify.txt
+++ b/test/passes/flatten_simplify-locals-nonesting_souperify_enable-threads.txt
diff --git a/test/passes/flatten_simplify-locals-nonesting_souperify.wast b/test/passes/flatten_simplify-locals-nonesting_souperify_enable-threads.wast
index bd1b825b6..bd1b825b6 100644
--- a/test/passes/flatten_simplify-locals-nonesting_souperify.wast
+++ b/test/passes/flatten_simplify-locals-nonesting_souperify_enable-threads.wast
diff --git a/test/passes/fuzz-exec.txt b/test/passes/fuzz-exec_enable-sign-ext.txt
index 409f93181..409f93181 100644
--- a/test/passes/fuzz-exec.txt
+++ b/test/passes/fuzz-exec_enable-sign-ext.txt
diff --git a/test/passes/fuzz-exec.wast b/test/passes/fuzz-exec_enable-sign-ext.wast
index 08042d2b9..08042d2b9 100644
--- a/test/passes/fuzz-exec.wast
+++ b/test/passes/fuzz-exec_enable-sign-ext.wast
diff --git a/test/passes/inlining-optimizing.txt b/test/passes/inlining-optimizing_enable-threads.txt
index 437870065..437870065 100644
--- a/test/passes/inlining-optimizing.txt
+++ b/test/passes/inlining-optimizing_enable-threads.txt
diff --git a/test/passes/inlining-optimizing.wast b/test/passes/inlining-optimizing_enable-threads.wast
index f0435baa4..f0435baa4 100644
--- a/test/passes/inlining-optimizing.wast
+++ b/test/passes/inlining-optimizing_enable-threads.wast
diff --git a/test/passes/optimize-instructions.txt b/test/passes/optimize-instructions_enable-threads.txt
index 67f0516fb..67f0516fb 100644
--- a/test/passes/optimize-instructions.txt
+++ b/test/passes/optimize-instructions_enable-threads.txt
diff --git a/test/passes/optimize-instructions.wast b/test/passes/optimize-instructions_enable-threads.wast
index fa683ca78..fa683ca78 100644
--- a/test/passes/optimize-instructions.wast
+++ b/test/passes/optimize-instructions_enable-threads.wast
diff --git a/test/passes/precompute.txt b/test/passes/precompute_enable-simd.txt
index f7f58f58f..f7f58f58f 100644
--- a/test/passes/precompute.txt
+++ b/test/passes/precompute_enable-simd.txt
diff --git a/test/passes/precompute.wast b/test/passes/precompute_enable-simd.wast
index d6b1cc1b7..d6b1cc1b7 100644
--- a/test/passes/precompute.wast
+++ b/test/passes/precompute_enable-simd.wast
diff --git a/test/passes/remove-unused-module-elements.txt b/test/passes/remove-unused-module-elements_enable-threads.txt
index c2471e743..c2471e743 100644
--- a/test/passes/remove-unused-module-elements.txt
+++ b/test/passes/remove-unused-module-elements_enable-threads.txt
diff --git a/test/passes/remove-unused-module-elements.wast b/test/passes/remove-unused-module-elements_enable-threads.wast
index 4bd5ccf10..4bd5ccf10 100644
--- a/test/passes/remove-unused-module-elements.wast
+++ b/test/passes/remove-unused-module-elements_enable-threads.wast
diff --git a/test/passes/remove-unused-names_merge-blocks.txt b/test/passes/remove-unused-names_merge-blocks_enable-threads.txt
index b60d01957..b60d01957 100644
--- a/test/passes/remove-unused-names_merge-blocks.txt
+++ b/test/passes/remove-unused-names_merge-blocks_enable-threads.txt
diff --git a/test/passes/remove-unused-names_merge-blocks.wast b/test/passes/remove-unused-names_merge-blocks_enable-threads.wast
index f9603a60d..f9603a60d 100644
--- a/test/passes/remove-unused-names_merge-blocks.wast
+++ b/test/passes/remove-unused-names_merge-blocks_enable-threads.wast
diff --git a/test/passes/remove-unused-nonfunction-module-elements.txt b/test/passes/remove-unused-nonfunction-module-elements_enable-threads.txt
index 2d9609efa..2d9609efa 100644
--- a/test/passes/remove-unused-nonfunction-module-elements.txt
+++ b/test/passes/remove-unused-nonfunction-module-elements_enable-threads.txt
diff --git a/test/passes/remove-unused-nonfunction-module-elements.wast b/test/passes/remove-unused-nonfunction-module-elements_enable-threads.wast
index 4370328ce..4370328ce 100644
--- a/test/passes/remove-unused-nonfunction-module-elements.wast
+++ b/test/passes/remove-unused-nonfunction-module-elements_enable-threads.wast
diff --git a/test/passes/safe-heap.txt b/test/passes/safe-heap_enable-threads_enable-simd.txt
index 1f9640ce2..1f9640ce2 100644
--- a/test/passes/safe-heap.txt
+++ b/test/passes/safe-heap_enable-threads_enable-simd.txt
diff --git a/test/passes/safe-heap.wast b/test/passes/safe-heap_enable-threads_enable-simd.wast
index 17c9995c4..17c9995c4 100644
--- a/test/passes/safe-heap.wast
+++ b/test/passes/safe-heap_enable-threads_enable-simd.wast
diff --git a/test/passes/safe-heap_low-memory-unused.txt b/test/passes/safe-heap_low-memory-unused_enable-threads_enable-simd.txt
index 469cf9f94..469cf9f94 100644
--- a/test/passes/safe-heap_low-memory-unused.txt
+++ b/test/passes/safe-heap_low-memory-unused_enable-threads_enable-simd.txt
diff --git a/test/passes/safe-heap_low-memory-unused.wast b/test/passes/safe-heap_low-memory-unused_enable-threads_enable-simd.wast
index 17c9995c4..17c9995c4 100644
--- a/test/passes/safe-heap_low-memory-unused.wast
+++ b/test/passes/safe-heap_low-memory-unused_enable-threads_enable-simd.wast
diff --git a/test/passes/simplify-locals.txt b/test/passes/simplify-locals_all-features.txt
index 7a6de1873..7a6de1873 100644
--- a/test/passes/simplify-locals.txt
+++ b/test/passes/simplify-locals_all-features.txt
diff --git a/test/passes/simplify-locals.wast b/test/passes/simplify-locals_all-features.wast
index 34a93d442..34a93d442 100644
--- a/test/passes/simplify-locals.wast
+++ b/test/passes/simplify-locals_all-features.wast
diff --git a/test/passes/ssa.txt b/test/passes/ssa_enable-threads.txt
index 54a5cd757..54a5cd757 100644
--- a/test/passes/ssa.txt
+++ b/test/passes/ssa_enable-threads.txt
diff --git a/test/passes/ssa.wast b/test/passes/ssa_enable-threads.wast
index bbfad89bf..bbfad89bf 100644
--- a/test/passes/ssa.wast
+++ b/test/passes/ssa_enable-threads.wast
diff --git a/test/passes/ssa_fuzz-exec.txt b/test/passes/ssa_fuzz-exec_enable-threads.txt
index 35499266e..35499266e 100644
--- a/test/passes/ssa_fuzz-exec.txt
+++ b/test/passes/ssa_fuzz-exec_enable-threads.txt
diff --git a/test/passes/ssa_fuzz-exec.wast b/test/passes/ssa_fuzz-exec_enable-threads.wast
index 1ad1e2a6f..1ad1e2a6f 100644
--- a/test/passes/ssa_fuzz-exec.wast
+++ b/test/passes/ssa_fuzz-exec_enable-threads.wast
diff --git a/test/passes/translate-to-fuzz.txt b/test/passes/translate-to-fuzz_all-features.txt
index fe24e738e..fe24e738e 100644
--- a/test/passes/translate-to-fuzz.txt
+++ b/test/passes/translate-to-fuzz_all-features.txt
diff --git a/test/passes/translate-to-fuzz.wast b/test/passes/translate-to-fuzz_all-features.wast
index 5b378f2b2..5b378f2b2 100644
--- a/test/passes/translate-to-fuzz.wast
+++ b/test/passes/translate-to-fuzz_all-features.wast
diff --git a/test/passes/translate-to-fuzz_no-fuzz-nans.txt b/test/passes/translate-to-fuzz_no-fuzz-nans_all-features.txt
index 294b4f986..294b4f986 100644
--- a/test/passes/translate-to-fuzz_no-fuzz-nans.txt
+++ b/test/passes/translate-to-fuzz_no-fuzz-nans_all-features.txt
diff --git a/test/passes/translate-to-fuzz_no-fuzz-nans.wast b/test/passes/translate-to-fuzz_no-fuzz-nans_all-features.wast
index cbf25fde1..cbf25fde1 100644
--- a/test/passes/translate-to-fuzz_no-fuzz-nans.wast
+++ b/test/passes/translate-to-fuzz_no-fuzz-nans_all-features.wast
diff --git a/test/unit/test_features.py b/test/unit/test_features.py
index 1672b957a..8764bef97 100644
--- a/test/unit/test_features.py
+++ b/test/unit/test_features.py
@@ -1,10 +1,9 @@
 import os
-import unittest
 from scripts.test.shared import WASM_OPT, run_process
-from utils import input_path, roundtrip
+from utils import BinaryenTestCase
 
 
-class FeatureValidationTest(unittest.TestCase):
+class FeatureValidationTest(BinaryenTestCase):
   def check_feature(self, module, error, flag):
     p = run_process(WASM_OPT + ['--mvp-features', '--print', '-o', os.devnull],
                     input=module, check=False, capture_output=True)
@@ -116,53 +115,50 @@ class FeatureValidationTest(unittest.TestCase):
     self.check_bulk_mem(module, 'nonzero segment flags (bulk memory is disabled)')
 
 
-class TargetFeaturesSectionTest(unittest.TestCase):
-  def disassemble(self, filename):
-    path = input_path(filename)
-    p = run_process(WASM_OPT + ['--print', '-o', os.devnull, path], check=False,
-                    capture_output=True)
-    self.assertEqual(p.returncode, 0)
-    self.assertEqual(p.stderr, '')
-    return p.stdout
-
+class TargetFeaturesSectionTest(BinaryenTestCase):
   def test_atomics(self):
-    roundtrip(self, 'atomics_target_feature.wasm')
-    module = self.disassemble('atomics_target_feature.wasm')
-    self.assertIn('i32.atomic.rmw.add', module)
+    filename = 'atomics_target_feature.wasm'
+    self.roundtrip(filename)
+    self.check_features(filename, ['threads'])
+    self.assertIn('i32.atomic.rmw.add', self.disassemble(filename))
 
   def test_bulk_memory(self):
-    roundtrip(self, 'bulkmem_target_feature.wasm')
-    module = self.disassemble('bulkmem_target_feature.wasm')
-    self.assertIn('memory.copy', module)
+    filename = 'bulkmem_target_feature.wasm'
+    self.roundtrip(filename)
+    self.check_features(filename, ['bulk-memory'])
+    self.assertIn('memory.copy', self.disassemble(filename))
 
   def test_nontrapping_fptoint(self):
-    roundtrip(self, 'truncsat_target_feature.wasm')
-    module = self.disassemble('truncsat_target_feature.wasm')
-    self.assertIn('i32.trunc_sat_f32_u', module)
+    filename = 'truncsat_target_feature.wasm'
+    self.roundtrip(filename)
+    self.check_features(filename, ['nontrapping-float-to-int'])
+    self.assertIn('i32.trunc_sat_f32_u', self.disassemble(filename))
 
   def test_sign_ext(self):
-    roundtrip(self, 'signext_target_feature.wasm')
-    module = self.disassemble('signext_target_feature.wasm')
-    self.assertIn('i32.extend8_s', module)
+    filename = 'signext_target_feature.wasm'
+    self.roundtrip(filename)
+    self.check_features(filename, ['sign-ext'])
+    self.assertIn('i32.extend8_s', self.disassemble(filename))
 
   def test_simd(self):
-    roundtrip(self, 'simd_target_feature.wasm')
-    module = self.disassemble('simd_target_feature.wasm')
-    self.assertIn('i32x4.splat', module)
+    filename = 'simd_target_feature.wasm'
+    self.roundtrip(filename)
+    self.check_features(filename, ['simd'])
+    self.assertIn('i32x4.splat', self.disassemble(filename))
 
   def test_incompatible_features(self):
-    path = input_path('signext_target_feature.wasm')
+    path = self.input_path('signext_target_feature.wasm')
     p = run_process(
-        WASM_OPT + ['--print', '-mvp', '--enable-simd', '-o', os.devnull, path],
+        WASM_OPT + ['--print', '--enable-simd', '-o', os.devnull, path],
         check=False, capture_output=True
     )
     self.assertNotEqual(p.returncode, 0)
-    self.assertIn('Fatal: module uses features not explicitly specified, ' +
-                  'use --detect-features to resolve',
+    self.assertIn('Fatal: module features do not match specified features. ' +
+                  'Use --detect-features to resolve.',
                   p.stderr)
 
   def test_incompatible_features_forced(self):
-    path = input_path('signext_target_feature.wasm')
+    path = self.input_path('signext_target_feature.wasm')
     p = run_process(
         WASM_OPT + ['--print', '--detect-features', '-mvp', '--enable-simd',
                     '-o', os.devnull, path],
@@ -172,11 +168,5 @@ class TargetFeaturesSectionTest(unittest.TestCase):
     self.assertIn('all used features should be allowed', p.stderr)
 
   def test_explicit_detect_features(self):
-    path = input_path('signext_target_feature.wasm')
-    p = run_process(
-        WASM_OPT + ['--print', '-mvp', '--detect-features',
-                    '-o', os.devnull, path],
-        check=False, capture_output=True
-    )
-    self.assertEqual(p.returncode, 0)
-    self.assertEqual(p.stderr, '')
+    self.check_features('signext_target_feature.wasm', ['sign-ext', 'simd'],
+                        opts=['-mvp', '--detect-features', '--enable-simd'])
diff --git a/test/unit/test_memory_packing.py b/test/unit/test_memory_packing.py
index 0d62b0ed5..a0ccd3006 100644
--- a/test/unit/test_memory_packing.py
+++ b/test/unit/test_memory_packing.py
@@ -1,12 +1,12 @@
 import os
-import unittest
 from scripts.test.shared import WASM_OPT, run_process
+from utils import BinaryenTestCase
 
 '''Test that MemoryPacking correctly respects the web limitations by not
 generating more than 100K data segments'''
 
 
-class MemoryPackingTest(unittest.TestCase):
+class MemoryPackingTest(BinaryenTestCase):
   def test_large_segment(self):
     data = '"' + (('A' + ('\\00' * 9)) * 100001) + '"'
     module = '''
diff --git a/test/unit/utils.py b/test/unit/utils.py
index eaeb29d42..876f2f4ec 100644
--- a/test/unit/utils.py
+++ b/test/unit/utils.py
@@ -1,16 +1,34 @@
 import os
+import unittest
 from scripts.test.shared import WASM_OPT, run_process, options
 
 
-def input_path(filename):
-  return os.path.join(options.binaryen_test, 'unit', 'input', filename)
+class BinaryenTestCase(unittest.TestCase):
+  def input_path(self, filename):
+    return os.path.join(options.binaryen_test, 'unit', 'input', filename)
 
+  def roundtrip(self, filename, opts=[]):
+    path = self.input_path(filename)
+    p = run_process(WASM_OPT + ['-g', '-o', '-', path] + opts, check=False,
+                    capture_output=True)
+    self.assertEqual(p.returncode, 0)
+    self.assertEqual(p.stderr, '')
+    with open(path, 'rb') as f:
+      self.assertEqual(str(p.stdout), str(f.read()))
 
-def roundtrip(testcase, filename, opts=[]):
-  path = input_path(filename)
-  p = run_process(WASM_OPT + ['-g', '-o', '-', path] + opts, check=False,
-                  capture_output=True)
-  testcase.assertEqual(p.returncode, 0)
-  testcase.assertEqual(p.stderr, '')
-  with open(path, 'rb') as f:
-    testcase.assertEqual(str(p.stdout), str(f.read()))
+  def disassemble(self, filename):
+    path = self.input_path(filename)
+    p = run_process(WASM_OPT + ['--print', '-o', os.devnull, path], check=False,
+                    capture_output=True)
+    self.assertEqual(p.returncode, 0)
+    self.assertEqual(p.stderr, '')
+    return p.stdout
+
+  def check_features(self, filename, features, opts=[]):
+    path = self.input_path(filename)
+    cmd = WASM_OPT + ['--print-features', '-o', os.devnull, path] + opts
+    p = run_process(cmd, check=False, capture_output=True)
+    self.assertEqual(p.returncode, 0)
+    self.assertEqual(p.stderr, '')
+    self.assertEqual(p.stdout.split('\n')[:-1],
+                     ['--enable-' + f for f in features])