What is the test for establishing substantial conflict in evidence?

"[T]he test is not the presence or absence of a substantial conflict in the evidence. Rather, it is simply whether there is substantial evidence in favor of the respondent. If this 'substantial' evidence is present, no matter how slight it may appear in comparison with the contradictory evidence, the judgment must be upheld. As a general rule, therefore, we will look only at the evidence and reasonable inferences supporting the successful party, and disregard the contrary showing." (Howard v. Owens Corning (1999) 72 Cal.App.4th 621, 631.)