What is the test for establishing that a defendant has good character?

Third, the trial court correctly concluded that even if the text messages might suggest some degree of bad character, defendant had rendered character evidence relevant by seeking to introduce evidence of his good character during cross-examination of prior witnesses. "A defendant who elicits character or reputation testimony opens the door to the prosecution's introduction of hearsay evidence that undermines testimony of his good reputation or of character inconsistent with the charged offense." (People v. Tuggles (2009) 179 Cal.App.4th 339, 357; see People v. Mitcham (1992) 1 Cal.4th 1027, 1072 ["By introducing evidence of good character, a defendant places his or her character in issue, thus opening the door to prosecution evidence tending to rebut that 'specific asserted aspect' of the defendant's character."].)