Looking for logging into the Test Salesforce site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Test Salesforce site. After that you can login as usual with your login credentials.
https://login.salesforce.com/?locale=de
https://developer.salesforce.com/forums/?id=906F00000008kVjIAI
https://mobile1.t.salesforce.com/
https://www.webassessor.com/wa.do?page=publicHome&branding=SALESFORCE
https://books.google.at/books?id=iMrstSdenCYC&pg=PT380&lpg=PT380&dq=test+login+salesforce
https://books.google.at/books?id=GFQnCgAAQBAJ&pg=PA266&lpg=PA266&dq=test+login+salesforce
https://books.google.at/books?id=8vxwDwAAQBAJ&pg=PA88&lpg=PA88&dq=test+login+salesforce
https://books.google.at/books?id=wAxJbOxylNIC&pg=PT479&lpg=PT479&dq=test+login+salesforce
https://books.google.at/books?id=cHWADwAAQBAJ&pg=PA54&lpg=PA54&dq=test+login+salesforce
https://workbench.developerforce.com/
https://stackoverflow.com/questions/41920326/cant-make-call-to-https-login-salesforce-com-services-oauth2-token-from-angula
https://stackoverflow.com/questions/35662599/login-to-salesforce-com-with-phantomjs-2-0-keep-asking-for-verification-code
https://stackoverflow.com/questions/4889953/salesforce-production-site-api-login-fine-but-sandbox-api-login-fails