Refactor tests to use t.TempDir and cleanup go.mod deps

[YoshihitoAso]

close #122

This pull request refactors the test codebase to use Go's t.TempDir() for managing temporary directories instead of manually creating and cleaning up directories with os.MkdirTemp and os.RemoveAll. This change simplifies test setup and teardown, reduces boilerplate, and makes the tests more robust and idiomatic. Additionally, a new linter (usetesting) is added to the configuration to encourage best practices in using the testing package.

Key changes include:

Testing improvements

• Replaced manual temporary directory management (os.MkdirTemp and os.RemoveAll) with t.TempDir() across all test files.

Linter configuration

• Added the usetesting linter to .golangci.yml to enforce and encourage idiomatic usage of the Go testing package, such as preferring t.TempDir() over manual directory management.

[Copilot]

Pull Request Overview

Refactors tests to use t.TempDir() and t.Setenv() for cleaner resource and environment handling, and adds the usetesting linter to enforce idiomatic testing patterns. Also adjusts module dependencies by removing github.com/docker/docker and making github.com/moby/sys/reexec a direct dependency.

• Replace manual temp dir and env var management with testing helpers (t.TempDir, t.Setenv)
• Add usetesting linter to .golangci.yml
• Update go.mod dependencies (remove docker/docker; promote moby/sys/reexec to direct)

Reviewed Changes

Copilot reviewed 53 out of 54 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
signer/storage/aes_gcm_storage_test.go	Replaced manual temp dir setup with t.TempDir
signer/fourbyte/fourbyte_test.go	Removed os import and used t.TempDir
signer/core/api_test.go	Simplified tmpDirName to use t.TempDir
rpc/security_test.go	Switched to t.Setenv but left redundant cleanup
rpc/client_test.go	Switched to t.Setenv but left redundant cleanup
raft/*.go tests	Replaced manual temp dir creation/cleanup with t.TempDir
private/private_test.go	Switched to t.Setenv
plugin/*_test.go	Adopted t.TempDir and t.Setenv patterns
permission/* tests	Replaced manual temp dir handling with t.TempDir
p2p/* tests	Adopted t.TempDir and minor variable handling updates
node/* tests	Replaced manual temp dir logic with t.TempDir
internal/* tests	Updated to t.TempDir / t.Setenv patterns
graphql/graphql_test.go	Simplified temp dir usage
extension/data_handler_test.go	Replaced manual temp dir logic with t.TempDir
eth/filters/filter_test.go	Used b.TempDir / t.TempDir for benchmarks and tests
crypto/* tests	Updated temp file creation to reside under t.TempDir
core/* tests	Broad refactor to use t.TempDir; some semantics changed where dirs were previously removed immediately
console/console_test.go	Replaced manual workspace cleanup with t.TempDir
common/http/config_test.go	Used t.TempDir for config files
cmd/utils/flags_test.go	Adopted t.TempDir
cmd/geth/* tests	Mixed changes; one cleanup path removal introduces a resource leak
accounts/keystore/* tests	Migrated helper functions to t.TempDir
accounts/abi/bind/bind_test.go	Simplified workspace creation with t.TempDir
.golangci.yml	Added usetesting linter
go.mod	Removed docker/docker and promoted moby/sys/reexec to direct dependency

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Pull Request Overview

Copilot reviewed 53 out of 54 changed files in this pull request and generated 6 comments.

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}