Add 404 get flag test

[zhouzhuojie]

Description

Add a simple unit test that covers #318

Motivation and Context

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov-io]

Codecov Report

Merging #337 into master will not change coverage by %.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #337   +/-   ##
=======================================
  Coverage   81.75%   81.75%           
=======================================
  Files          26       26           
  Lines        1540     1540           
=======================================
  Hits         1259     1259           
  Misses        211      211           
  Partials       70       70           

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