diff --git a/tests/core/gen_helpers/gen_base/gen_runner.py b/tests/core/gen_helpers/gen_base/gen_runner.py
index a22073c00..1cf8ba8cf 100644
--- a/tests/core/gen_helpers/gen_base/gen_runner.py
+++ b/tests/core/gen_helpers/gen_base/gen_runner.py
@@ -9,6 +9,7 @@ from ruamel.yaml import (
 )
 
 from gen_base.gen_typing import TestProvider
+from snappy import compress
 
 from eth2spec.test import context
 from eth2spec.test.exceptions import SkippedTest
@@ -180,7 +181,8 @@ def dump_yaml_fn(data: Any, name: str, file_mode: str, yaml_encoder: YAML):
 
 def dump_ssz_fn(data: AnyStr, name: str, file_mode: str):
     def dump(case_path: Path):
-        out_path = case_path / Path(name + '.ssz')
+        out_path = case_path / Path(name + '.ssz_snappy')
+        compressed = compress(data)
         with out_path.open(file_mode + 'b') as f:  # write in raw binary mode
-            f.write(data)
+            f.write(compressed)
     return dump
diff --git a/tests/core/gen_helpers/requirements.txt b/tests/core/gen_helpers/requirements.txt
index e7cdd30ea..a2c194dea 100644
--- a/tests/core/gen_helpers/requirements.txt
+++ b/tests/core/gen_helpers/requirements.txt
@@ -1,3 +1,4 @@
 ruamel.yaml==0.16.5
 eth-utils==1.6.0
 pytest>=4.4
+python-snappy==0.5.4
diff --git a/tests/core/gen_helpers/setup.py b/tests/core/gen_helpers/setup.py
index e9fc1a787..d26530642 100644
--- a/tests/core/gen_helpers/setup.py
+++ b/tests/core/gen_helpers/setup.py
@@ -7,5 +7,6 @@ setup(
         "ruamel.yaml==0.16.5",
         "eth-utils==1.6.0",
         "pytest>=4.4",
+        "python-snappy==0.5.4",
     ]
 )
diff --git a/tests/core/pyspec/eth2spec/test/utils.py b/tests/core/pyspec/eth2spec/test/utils.py
index 12ff68443..306f7d892 100644
--- a/tests/core/pyspec/eth2spec/test/utils.py
+++ b/tests/core/pyspec/eth2spec/test/utils.py
@@ -39,24 +39,20 @@ def vector_test(description: str = None):
                     if value is None:
                         continue
                     if isinstance(value, View):
-                        yield key, 'data', encode(value)
                         yield key, 'ssz', serialize(value)
                     elif isinstance(value, bytes):
-                        yield key, 'data', encode(value)
                         yield key, 'ssz', value
                     elif isinstance(value, list) and all([isinstance(el, (View, bytes)) for el in value]):
                         for i, el in enumerate(value):
                             if isinstance(el, View):
-                                yield f'{key}_{i}', 'data', encode(el)
                                 yield f'{key}_{i}', 'ssz', serialize(el)
                             elif isinstance(el, bytes):
-                                yield f'{key}_{i}', 'data', encode(el)
                                 yield f'{key}_{i}', 'ssz', el
                         yield f'{key}_count', 'meta', len(value)
                     else:
                         # Not a ssz value.
                         # The data will now just be yielded as any python data,
-                        #  something that should be encodeable by the generator runner.
+                        #  something that should be encodable by the generator runner.
                         yield key, 'data', value
 
             # check generator mode, may be None/else.