diff --git a/features/steps/core.py b/features/steps/core.py
index f6c54564..1b476a2a 100644
--- a/features/steps/core.py
+++ b/features/steps/core.py
@@ -66,15 +66,15 @@ def no_error(context):
 @then('the output should be parsable as json')
 def check_output_json(context):
     out = context.stdout_capture.getvalue()
-    assert json.loads(out)
+    assert json.loads(out), out
 
 @then('"{field}" in the json output should have {number:d} elements')
 @then('"{field}" in the json output should have 1 element')
 def check_output_field(context, field, number=1):
     out = context.stdout_capture.getvalue()
     out_json = json.loads(out)
-    assert field in out_json
-    assert len(out_json[field]) == number
+    assert field in out_json [field, out_json]
+    assert len(out_json[field]) == number, len(out_json[field])
 
 @then('"{field}" in the json output should not contain "{key}"')
 def check_output_field_not_key(context, field, key):
@@ -95,7 +95,7 @@ def check_output(context):
     text = context.text.strip().splitlines()
     out = context.stdout_capture.getvalue().strip().splitlines()
     for line_text, line_out in zip(text, out):
-        assert line_text.strip() == line_out.strip()
+        assert line_text.strip() == line_out.strip(), [line_text.strip(), line_out.strip()]
 
 @then('the output should contain "{text}"')
 def check_output_inline(context, text):