The response was built by concatenating the request path into a JSON
string. The path is percent-decoded, so it can contain quotes and
backslashes, which produced malformed JSON and let a caller inject
arbitrary keys into the object.
Satisfies errcheck. Errors that carry no actionable information are
ignored explicitly: writes to an already-committed response, and closing
a fully read response body or file.
Test fixture setup asserts with require.NoError instead, since a failure
there means the fixture itself is broken.
Trong Huu Nguyen