assert.YAMLEq: handle multi documents

[brackendawson]

Summary

In YAMLEq(), yaml documents in the input after the first document were silently not considered in the comparison. Make it compare all the docs.

I checked JSONEq() and it always fails if you try to pass it JSON Lines documents, even if they are the same.

Changes

• Use a yaml.Decoder.Decode() loop into a []interface{} rather than a yaml.Unmarshal() into an interface{}.

Motivation

Unlike with passing JSON Lines inputs to JSONEq(), which always fails, passing multiple YAML documents with differences after the first document into YAMLEq() silently passes. 😱

Related issues

Closes #1281

[dolmen]

LGTM. Please rebase on master.

[dolmen]

Related: #1755 (also changes YAMLEq)

[dolmen]

This patch has been broken by #1579 which made the YAML library pluggable.

Updating the patch requires changing the interface for pluggable YAML lib as yaml.Unmarshal doesn't support multidocs: this patch uses a yaml.Decoder, so rebasing is not trvial.

[brackendawson]

Because #1579 exposed the internal implementation of YAMLEq on testify's API, it is not possible to solve this issue without either partially implementing a YAML parser in testify itself or changing testify's API in one of two ways:

• Change assert.yaml.Unmarshal to a decoder. This would be a breaking change so no.
• Add another YAML assertion (like YAMLEqAll) that uses decode. I dislike this because we shouldn't have added YAMLEq in the first place.

I'm closing this PR because it's no longer tenable.