[ffumero2003]

Context

Part of the test-integrity audit (#97). #204 is a checklist of tests that check less than their names say. This PR covers the b2/b2_test.go items of its ### b2 section (slice C1). Sibling PRs: #232 (base, merged), #233 (b2/sync, x, internal, merged), #240 (b2 API, merged), #248 (live tests and twins), #249 (production edges), and C4 (writer, reader and progress, in progress).

What each test now proves

Every claim below is backed by the assertion named, and by a break in the Verification table that fails it.

Item	Test	What it now asserts
Upload attempt cap	TestWriterLimitNewUploadAttempts	With one worker, exactly six uploadPart attempts (the first plus five reuploads). With two workers, two parts start concurrently and no part exceeds six attempts.
Read after double Close	TestReaderDoubleClose	Closes before EOF, then requires Read to return zero bytes and an error or EOF.
Fake-echo bucket tests	TestNewBucketCORSAndFileLock	Through the recording server: the locked bucket's b2_create_bucket body carries corsRules and fileLockEnabled: true; the plain bucket's body omits both (per the b2_create_bucket docs, CORS is optional and file lock defaults to false); Attrs sends b2_list_buckets filtered by bucketName ("locked", then "plain") and reads each bucket's own settings.
Bucket ID	TestBucketID	Literal IDs from the create and list responses; looking up the ID makes no request.
Invalid bucket encryption	TestBucketDefaultEncryptionRejected	The exact validation error. NewBucket sends one b2_list_buckets (it lists first, by design) and zero b2_create_bucket / b2_update_bucket for a rejected setting, for both a new and an existing bucket.
Backoff	TestBackoff, TestBackoffWithoutRetryAfter, TestBackoffWithMaxRetriesReached	The requested delays, captured through the existing wait hook: Retry-After exactly, the jitter bounds of the first retry, and the 30-second cap. Before, they counted waits only, so forcing every delay to 1ns passed.
Delete bypass	TestObjectDeleteBypassGovernanceReachesTheWire (unchanged)	Already asserts fileId, fileName and bypassGovernance on the wire, so the fake-only test is removed.

Moved out: item 1, TestWriterReturnsError. Its stronger assertion exposed a product bug (io.Copy into a Writer returned context canceled instead of the upload error), filed as #245 and fixed in #252, which tightens that test.

Tests removed, and what covers them now

Removed	Covered by
TestObjectDeleteBypassGovernanceOption (asserted a bool recorded by the fake)	TestObjectDeleteBypassGovernanceReachesTheWire (b2/delete_bypass_wire_test.go)
TestNewBucketReplicationConfig (the fake echoed its arguments)	TestNewBucketReplicationConfigurationWireRoundTrip (b2/replication_create_wire_test.go)
TestBucketAttrsCORSAndFileLockPerBucket (fake-only)	TestNewBucketCORSAndFileLock, which now asserts the request bodies through the recording server

No assertion was narrowed elsewhere: the single-worker upload-cap case stays, and the two-worker case was added alongside it.

Verification

Each break was applied alone; the named test failed, then passed after revert. ("b2/b2.go:446" in 4c and 4d is the if bucket.name() == name match in Client.Bucket.)

Item	Break	Failing output
2a	Reupload limit +1 → +2	uploadPart attempts = 7, want 6 (initial attempt plus five reuploads)
2b	Initial-attempt guard flipped	uploadPart attempts = 1, want 6 (initial attempt plus five reuploads)
2c	Initial-attempt guard deleted	uploadPart attempts = 1, want 6 (initial attempt plus five reuploads)
2d	b2/writer.go:952 reupload cap +1 → +2, two workers	uploadPart:1 attempts = 7, want at most 6; uploadPart:2 attempts = 7, want at most 6
3a	Reader.Read returns (0, nil) after Close	Read after Close = 0, <nil>; want 0 and an error or EOF
3b	Reader.Read returns (1, nil) after Close	Read after Close = 1, <nil>; want 0 and an error or EOF
4a	Omit CORS in create mapping	b2_create_bucket body corsRules: missing, want [{"allowedHeaders":["authorization"],"allowedOperations":["b2_download_file_by_name"],"allowedOrigins":["https://example.com"],"corsRuleName":"browser","exposeHeaders":["x-bz-file-name"],"maxAgeSeconds":60}]
4b	Omit file lock in create mapping	b2_create_bucket body fileLockEnabled: missing, want true
4c	b2/b2.go:446, Client.Bucket name-match condition if bucket.name() == name flipped	Bucket.Attrs().FileLockEnabled = false, want true
4d	b2/b2.go:446, same Client.Bucket name-match condition removed so the first listed bucket returns unconditionally	plain bucket attrs = … FileLockEnabled:true …, want no CORS rules and no file lock
4e	Omit replication in create mapping	create omitted replicationConfiguration
4f	base/base.go:829 sends a CORS rule for the plain create	b2_create_bucket body corsRules: got [{"corsRuleName":"unexpected"}], want missing
4g	base/base.go:830 forces fileLockEnabled: true for the plain create	b2_create_bucket body fileLockEnabled: got true, want missing
4h	b2/baseline.go:278 drops the name passed to ListBuckets	b2_list_buckets body bucketName: missing, want "locked"; … want "plain"
5a	Bypass option assignment flipped to false	Delete(BypassGovernance) sent bypassGovernance = <nil>, want true
5b	Bypass option assignment deleted	Delete(BypassGovernance) sent bypassGovernance = <nil>, want true
7a	NewBucket encryption guard flipped	invalid default sent 1 create requests, want 0
7b	NewBucket encryption guard deleted	invalid default sent 1 create requests, want 0
7c	Update encryption guard flipped	invalid default sent 1 update requests, want 0
7d	Update encryption guard deleted	invalid default sent 1 update requests, want 0
7e	Move NewBucket encryption validation before b2/b2.go:465 list	NewBucket listed 0 times, want 1
7f	Flip b2/b2.go:470 existing-bucket name match	NewBucket(existing) sent 1 create requests, want 0
8a	Force backend delay to 1ns; TestBackoff	wait 1 = 1ns, want [1s, 1s]; wait 2 = 1ns, want [2s, 2s]; wait 1 = 1ns, want [1.01s, 1.03s]
8b	Force backend delay to 1ns; TestBackoffWithoutRetryAfter	wait 1 = 1ns, want [1.01s, 1.03s]; wait 7 = 1ns, want [30s, 32s]
8c	Force backend delay to 1ns; TestBackoffWithMaxRetriesReached	wait 1 = 1ns, want [1.01s, 1.03s]; wait 2 = 1ns, want [2.04s, 2.122s]
8d	First-delay guard flipped	wait 1 = 0s, want [1.01s, 1.03s]
8e	First-delay guard deleted	wait 1 = 0s, want [1.01s, 1.03s]
8f	Retry-After guard flipped	wait 1 = 1.011091425s, want [1s, 1s]
8g	Retry-After guard deleted	wait 1 = 1.02398841s, want [1s, 1s]
8h	30-second cap guard flipped	wait 1 = 30.010863997s, want [1.01s, 1.03s]
8i	30-second cap guard deleted	wait 7 = 1m11.547314088s, want [30s, 32s]; wait 8 = 2m26.982487425s, want [30s, 32s]

With no B2 credentials set: go test -race -count=5 -shuffle=on ./b2/... passes, and the changed timing and concurrency tests pass 30 runs in a row under -race.

make ci (tail)

go build ./...
go vet ./...
go mod tidy -diff
go mod verify
all modules verified
0 issues.
go test -race -shuffle=on ./...
ok  	github.com/Backblaze/blazer/b2	15.605s
ok  	github.com/Backblaze/blazer/b2/sync	5.048s
ok  	github.com/Backblaze/blazer/base	7.533s
ok  	github.com/Backblaze/blazer/internal/b2types	2.702s
ok  	github.com/Backblaze/blazer/internal/b2wiretest	2.268s
ok  	github.com/Backblaze/blazer/internal/blog	1.435s
ok  	github.com/Backblaze/blazer/internal/retry	2.861s
ok  	github.com/Backblaze/blazer/x/b2sim	3.617s
ok  	github.com/Backblaze/blazer/x/consistent	2.567s
ok  	github.com/Backblaze/blazer/x/transport	3.291s
ok  	github.com/Backblaze/blazer/x/window	2.313s
CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build ./...
CGO_ENABLED=0 GOOS=linux GOARCH=386 go build ./...
CGO_ENABLED=0 GOOS=linux GOARCH=arm go build ./...
CGO_ENABLED=0 GOOS=darwin GOARCH=arm64 go build ./...
CGO_ENABLED=0 GOOS=windows GOARCH=amd64 go build ./...
... scripts/*_test.sh: all ok

Part of #204

[david-santacruz-backblaze]

Let's review these issues pls.

• The PR body mentions the bypass twin asserting fileId and fileName, but it looks like it only checks bypassGovernance. Maybe worth a look at the wording, or at adding those assertions?
• plan.md doesn't seem to have mutation rows for TestReaderDoubleClose where Read after Close returns 0, nil or 1, nil. Row 3 only shows a hang. Could be nice to add them.
• TestBucketDefaultEncryptionRejected: NewBucket still sends b2_list_buckets, so "no request is sent" might be a bit strong. The existing-bucket subcase also doesn't assert request counts.
• TestNewBucketCORSAndFileLock doesn't seem to assert the plain bucket's create body.
• The PR body says per-bucket attribute reads assert the request body, but it looks like only create bodies are asserted.
• plan.md rows 4c and 4d mention a "Bucket-name guard" that I couldn't match to the diff. Which guard is it?
• TestWriterLimitNewUploadAttempts now runs with ConcurrentUploads=1, so concurrent cap behaviour may no longer be covered. Maybe worth a quick look?
• Minor: I haven't run make ci or the 25-row mutation table, so those are unverified on my side.

[ffumero2003]

@david-santacruz-backblaze Thanks, all addressed (5a572f0, 0c3e739), and the branch is synced with main. I rewrote the description from the final diff: each claim now maps to the assertion that proves it, and there is a table of the removed tests and what covers them.

1. Bypass twin fileId/fileName: after syncing with main (test(b2): tighten API-facing b2 test assertions #240 added them), TestObjectDeleteBypassGovernanceReachesTheWire asserts fileId, fileName and bypassGovernance. No duplicates added.
2. TestReaderDoubleClose: added breaks where Read after Close returns (0, nil) and (1, nil). Both fail: Read after Close = 0, <nil>; want 0 and an error or EOF (and the same with 1).
3. TestBucketDefaultEncryptionRejected: fixed. It now asserts exact counts: one b2_list_buckets (NewBucket lists first) and zero b2_create_bucket / b2_update_bucket for rejected settings, in both the new- and existing-bucket subcases. The wording now says "no create or update request". Moving validation before the list fails with NewBucket listed 0 times, want 1; re-creating an existing bucket fails with sent 1 create requests, want 0.
4. Plain bucket create body: added. It omits corsRules and fileLockEnabled, per the b2_create_bucket docs. Breaks fail with corsRules: got [...], want missing and fileLockEnabled: got true, want missing.
5. Per-bucket attribute reads: now assert the request. b2_list_buckets is filtered by bucketName ("locked", then "plain"); dropping the name fails with bucketName: missing, want "locked".
6. "Bucket-name guard": that is if bucket.name() == name in Client.Bucket (b2/b2.go:446). Rows 4c and 4d now name it.
7. Concurrent cap: restored. TestWriterLimitNewUploadAttempts keeps the single-worker exact-count case and adds a two-worker case: two parts start concurrently and no part exceeds six attempts. Raising the cap fails with uploadPart:1 attempts = 7, want at most 6.

Also, as on #248 and #249: the intent folder is removed (the table is in the description), and the make ci tail is in the description.