llvm/llvm/test/tools/yaml2obj/preprocess-only.test

# RUN: yaml2obj -E -Dfoo=wibble %s | FileCheck %s

This is a test of yaml2obj's pure preprocessing mode, so it doesn't
have to contain valid YAML, or any YAML at all. But we do have to be
careful with the FileCheck CHECK directives, because they'll be
emitted into the preprocessed output, and risk matching themselves!
For that reason, each one matches only at the start of a line.

Expand a macro:
[[foo]]            # CHECK: {{^wibble}}

Expand an undefined macro:
[[bar]]            # CHECK: {{^\[\[bar\]\]}}

Expand an undefined macro where we provided a default value:
[[baz=123]]        # CHECK: {{^123}}