Is it true if a man takes pregnancy test and comes backs positive does that mean testicular cancer?

No, that doesn't indicate testicular cancer. Men cannot become pregnant because they don't have a uterus which is required for gestation of a fetus to occur.

Testicular cancers are characterized by tumors formed in testes and usually don't involve positive pregnancy test.

Pregnancy tests detect the presence of a hormone called human chorionic gonadrotopin (hCG), which rises steeply in early pregnancy.

In men pregnancy test can only give false positive because of certain medical treatments such as fertility therapies or due to underlying health conditions affecting hormone levels..