| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/stretchr/testify/assert | Package assert provides a set of comprehensive testing tools for use with the normal Go testing system. |
| github.com/stretchr/testify/require | Package require implements the same assertions as the `assert` package but stops test execution when a test fails. |
| image | Package image implements a basic 2-D image library. |
| image/color | Package color implements a basic color library. |
| image/png | Package png implements a PNG image decoder and encoder. |
| math | Package math provides basic constants and mathematical functions. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| path/filepath | Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths. |
| testing | Package testing provides support for automated testing of Go packages. |