test: Simplify the function that skips integration tests

[alexandear]

This PR refactors integration tests:

• Refactor checkAuth function in by passing *testing.T parameter and renaming for clarity.
• Simplifying client and auth initialization by using sync.OnceValues.
• Fix TestAPIMeta which fails if run without OAuth token.

Running integration tests locally

TestAPIMeta without token:

❯ go test -tags=integration -count=1 -v -run=TestAPIMeta ./test/integration/...
=== RUN   TestAPIMeta
--- PASS: TestAPIMeta (0.28s)
PASS
ok      github.com/google/go-github/v75/test/integration        0.860s

TestAPIMeta with token:

❯ GITHUB_AUTH_TOKEN=ghp_... go test -tags=integration -count=1 -v -run=TestAPIMeta ./test/integration/...
=== RUN   TestAPIMeta
--- PASS: TestAPIMeta (0.28s)
PASS
ok      github.com/google/go-github/v75/test/integration        0.860s

All tests without token:

❯ go test -tags=integration -count=1 -v ./test/integration/...
=== RUN   TestActivity_Starring
    github_test.go:34: No OAuth token - skipping portions of TestActivity_Starring
--- SKIP: TestActivity_Starring (0.30s)
=== RUN   TestActivity_Watching
    github_test.go:34: No OAuth token - skipping portions of TestActivity_Watching
--- SKIP: TestActivity_Watching (0.20s)
=== RUN   TestOrganizationAuditLog
    github_test.go:34: No OAuth token - skipping portions of TestOrganizationAuditLog
--- SKIP: TestOrganizationAuditLog (0.00s)
=== RUN   TestAuthorizationsAppOperations
    authorizations_test.go:130: Skipping test because the required environment variable (GITHUB_CLIENT_ID) is not present.
--- SKIP: TestAuthorizationsAppOperations (0.00s)
=== RUN   TestIssueEvents
--- PASS: TestIssueEvents (1.06s)
=== RUN   TestEmojis
--- PASS: TestEmojis (0.17s)
=== RUN   TestAPIMeta
--- PASS: TestAPIMeta (0.16s)
=== RUN   TestRateLimits
--- PASS: TestRateLimits (0.04s)
=== RUN   TestPullRequests_ListCommits
--- PASS: TestPullRequests_ListCommits (0.26s)
=== RUN   TestRepositories_CRUD
    github_test.go:34: No OAuth token - skipping portions of TestRepositories_CRUD
--- SKIP: TestRepositories_CRUD (0.00s)
=== RUN   TestRepositories_BranchesTags
--- PASS: TestRepositories_BranchesTags (0.65s)
=== RUN   TestRepositories_EditBranches
    github_test.go:34: No OAuth token - skipping portions of TestRepositories_EditBranches
--- SKIP: TestRepositories_EditBranches (0.00s)
=== RUN   TestRepositories_ListByAuthenticatedUser
    github_test.go:34: No OAuth token - skipping portions of TestRepositories_ListByAuthenticatedUser
--- SKIP: TestRepositories_ListByAuthenticatedUser (0.00s)
=== RUN   TestRepositories_ListByUser
--- PASS: TestRepositories_ListByUser (0.65s)
=== RUN   TestRepositories_DownloadReleaseAsset
    github_test.go:34: No OAuth token - skipping portions of TestRepositories_DownloadReleaseAsset
--- SKIP: TestRepositories_DownloadReleaseAsset (0.00s)
=== RUN   TestRepositories_Autolinks
    github_test.go:34: No OAuth token - skipping portions of TestRepositories_Autolinks
--- SKIP: TestRepositories_Autolinks (0.00s)
=== RUN   TestUsers_Get
--- PASS: TestUsers_Get (0.34s)
=== RUN   TestUsers_Update
    github_test.go:34: No OAuth token - skipping portions of TestUsers_Update
--- SKIP: TestUsers_Update (0.00s)
=== RUN   TestUsers_Emails
    github_test.go:34: No OAuth token - skipping portions of TestUsers_Emails
--- SKIP: TestUsers_Emails (0.00s)
=== RUN   TestUsers_Keys
    github_test.go:34: No OAuth token - skipping portions of TestUsers_Keys
--- SKIP: TestUsers_Keys (0.16s)
PASS
ok      github.com/google/go-github/v75/test/integration        4.347s

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.11%. Comparing base (233fe03) to head (9c77662).
⚠️ Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3752   +/-   ##
=======================================
  Coverage   91.11%   91.11%           
=======================================
  Files         187      187           
  Lines       16702    16702           
=======================================
  Hits        15218    15218           
  Misses       1296     1296           
  Partials      188      188           

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[gmlewis]

What's the story with the complete reversal on this one?
Do we need to add a comment? Or was it just plain broken?

[alexandear]

verifiable_password_authentication is false for github.com since February 14, 2020. So yeah, the test seems broken for 4.5 years.

I found this information on:

• https://developer.github.com/changes/2020-02-14-deprecating-password-auth/
• https://developer.github.com/changes/2020-02-14-deprecating-oauth-auth-endpoint/
• GitHub Desktop authentication primarily through browser flow desktop/desktop#9231
• https://docs2.lfe.io/v3/meta/#:~:text=GitHub%20Enterprise%20instances%20using%20CAS%20or%20OAuth%20for%20authentication%20will%20return%20false

[alexandear]

@gmlewis I can remove this check at all:

	if *meta.VerifiablePasswordAuthentication {
		t.Error("APIMeta VerifiablePasswordAuthentication is true")
	}

The test will still be valuable.

[gmlewis]

That's OK. We can leave it as it will be good-to-know for people who were not aware of the change in 2020.

Thank you, @alexandear!

[gmlewis]

Thank you, @alexandear!
LGTM.
Merging.