fix(certificatee): use fmt.Fprintf instead of Write+Sprintf in test

[ananthb]

What changed

Replace w.Write([]byte(fmt.Sprintf(...))) with fmt.Fprintf(w, ...) in a test helper.

Why

golangci-lint (staticcheck QF1012) has been failing on master since PR #38 (fix(certificatee): match haproxy certs by SAN, 2026-07-04), which introduced this pattern. It's been blocking CI on every subsequent PR/master run, including #40.

No Linear ticket - CI fix.

[github-actions]

Code Coverage Report

Total Coverage: total: (statements) 50.7%

Coverage by function

github.com/vinted/certificator/cmd/certificatee/health.go:27:		newCertificateeHealthChecker		100.0%
github.com/vinted/certificator/cmd/certificatee/health.go:38:		certificateeHealthMaxSyncAge		75.0%
github.com/vinted/certificator/cmd/certificatee/health.go:46:		Check					87.5%
github.com/vinted/certificator/cmd/certificatee/health.go:78:		MarkEndpointSyncSuccess			80.0%
github.com/vinted/certificator/cmd/certificatee/health.go:88:		lastSync				100.0%
github.com/vinted/certificator/cmd/certificatee/helpers.go:9:		createHAProxyClients			0.0%
github.com/vinted/certificator/cmd/certificatee/main.go:45:		Error					100.0%
github.com/vinted/certificator/cmd/certificatee/main.go:49:		Unwrap					100.0%
github.com/vinted/certificator/cmd/certificatee/main.go:53:		main					0.0%
github.com/vinted/certificator/cmd/certificatee/main.go:105:		maybeUpdateCertificates			0.0%
github.com/vinted/certificator/cmd/certificatee/main.go:121:		processHAProxyEndpoint			71.4%
github.com/vinted/certificator/cmd/certificatee/main.go:228:		setDataPlaneAPIVersion			100.0%
github.com/vinted/certificator/cmd/certificatee/main.go:238:		domainFromCertificateName		100.0%
github.com/vinted/certificator/cmd/certificatee/main.go:243:		domainsForVault				91.7%
github.com/vinted/certificator/cmd/certificatee/main.go:264:		certificateDomains			66.7%
github.com/vinted/certificator/cmd/certificatee/main.go:272:		parseCertificateDomainList		77.8%
github.com/vinted/certificator/cmd/certificatee/main.go:304:		shouldUpdateForLiveExpiry		100.0%
github.com/vinted/certificator/cmd/certificatee/main.go:322:		shouldUpdateForSerialMismatch		100.0%
github.com/vinted/certificator/cmd/certificatee/main.go:332:		validateVaultCertificateForUpdate	100.0%
github.com/vinted/certificator/cmd/certificatee/main.go:336:		validateVaultCertificateForUpdateAt	91.7%
github.com/vinted/certificator/cmd/certificatee/main.go:361:		expectedVaultCertificateDomains		83.3%
github.com/vinted/certificator/cmd/certificatee/main.go:374:		vaultCertificateMatchesDomains		100.0%
github.com/vinted/certificator/cmd/certificatee/main.go:387:		parseVaultLeafCertificate		100.0%
github.com/vinted/certificator/cmd/certificatee/main.go:396:		readVaultCertificateBundle		85.7%
github.com/vinted/certificator/cmd/certificatee/main.go:410:		readValidVaultCertificateBundle		92.3%
github.com/vinted/certificator/cmd/certificatee/main.go:438:		firstDomain				66.7%
github.com/vinted/certificator/cmd/certificatee/main.go:446:		syncCertificate				85.7%
github.com/vinted/certificator/cmd/certificatee/main.go:495:		buildPEMBundle				70.0%
github.com/vinted/certificator/cmd/certificatee/main.go:521:		endsWith				66.7%
github.com/vinted/certificator/cmd/certificator/main.go:28:		main					0.0%
github.com/vinted/certificator/cmd/certificator/main.go:112:		deleteExpiredVaultCertificate		0.0%
github.com/vinted/certificator/cmd/certificator/main.go:116:		deleteExpiredVaultCertificateAt		100.0%
github.com/vinted/certificator/pkg/acme/acme.go:27:			GetEmail				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:32:			GetRegistration				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:37:			GetPrivateKey				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:42:			NewClient				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:61:			setupClient				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:80:			setupAccount				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:118:			newAccount				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:130:			getAccountKey				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:159:			registerAccount				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:177:			recoverAccount				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:211:			saveAccount				0.0%
github.com/vinted/certificator/pkg/acme/acme.go:221:			saveKey					0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:18:	ObtainCertificate			0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:50:	GetCertificate				0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:63:	ParsePEMCertificate			0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:80:	DeleteCertificate			0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:85:	IsExpired				0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:91:	NeedsReissuing				0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:119:	arraysEqual				0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:133:	arrayContains				0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:142:	VaultCertLocation			0.0%
github.com/vinted/certificator/pkg/certificate/certificate.go:146:	storeCertificateInVault			0.0%
github.com/vinted/certificator/pkg/certmetrics/metrics.go:79:		StartMetricsServer			0.0%
github.com/vinted/certificator/pkg/certmetrics/metrics.go:104:		newHandler				100.0%
github.com/vinted/certificator/pkg/certmetrics/metrics.go:128:		PushMetrics				0.0%
github.com/vinted/certificator/pkg/config/config.go:73:			LoadConfig				0.0%
github.com/vinted/certificator/pkg/haproxy/client.go:57:		Error					0.0%
github.com/vinted/certificator/pkg/haproxy/client.go:63:		IsHTTPStatus				100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:68:		unexpectedStatusError			100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:77:		NewClient				100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:112:		NewClients				92.3%
github.com/vinted/certificator/pkg/haproxy/client.go:137:		Endpoint				100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:142:		doRequest				88.9%
github.com/vinted/certificator/pkg/haproxy/client.go:160:		parseAPITime				66.7%
github.com/vinted/certificator/pkg/haproxy/client.go:173:		getConfigVersion			66.7%
github.com/vinted/certificator/pkg/haproxy/client.go:240:		ListCertificates			100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:254:		ListCertificateRefs			90.9%
github.com/vinted/certificator/pkg/haproxy/client.go:296:		GetCertificateDetail			68.4%
github.com/vinted/certificator/pkg/haproxy/client.go:340:		UpdateCertificate			80.0%
github.com/vinted/certificator/pkg/haproxy/client.go:374:		UpdateStorageCertificate		90.9%
github.com/vinted/certificator/pkg/haproxy/client.go:393:		CreateCertificate			78.9%
github.com/vinted/certificator/pkg/haproxy/client.go:426:		EnsureStorageCertificate		50.0%
github.com/vinted/certificator/pkg/haproxy/client.go:444:		DeleteCertificate			92.9%
github.com/vinted/certificator/pkg/haproxy/client.go:468:		ExtractDomainFromPath			100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:488:		NormalizeDomainForVault			0.0%
github.com/vinted/certificator/pkg/haproxy/client.go:495:		StorageCertificateName			100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:501:		IsExpiring				100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:513:		NormalizeSerial				100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:546:		Error					100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:550:		Info					0.0%
github.com/vinted/certificator/pkg/haproxy/client.go:554:		Debug					100.0%
github.com/vinted/certificator/pkg/haproxy/client.go:558:		Warn					0.0%
github.com/vinted/certificator/pkg/haproxy/client.go:563:		toLogrusFields				85.7%
github.com/vinted/certificator/pkg/vault/vault.go:18:			NewVaultClient				0.0%
github.com/vinted/certificator/pkg/vault/vault.go:27:			TokenLookupSelf				0.0%
github.com/vinted/certificator/pkg/vault/vault.go:39:			KVWrite					0.0%
github.com/vinted/certificator/pkg/vault/vault.go:53:			KVDelete				0.0%
github.com/vinted/certificator/pkg/vault/vault.go:66:			KVRead					0.0%
github.com/vinted/certificator/pkg/vault/vault.go:87:			vaultFullPath				0.0%
total:									(statements)				50.7%