test: add test codes using gov handler

[dongsam]

Description

closes: #58

Tasks

• add test codes to budget plan works as expected after modified by gov
• refactor test variables
• apply suggestions from feat: add address endpoint and release swagger v1.0.0 #90

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
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• Appropriate labels applied
• Targeted PR against correct branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[jaybxyz]

LGTM