if you are referring to the test for the AC position in London, until the end of last year it was structured in two parts. The first part is related to a personality test. The second is related to logical, numerical and verbal reasoning sections. Logical and numerical are SHL-style, unlike the other parts.
Bain also has a different test in South America, also divided into two parts. The first part is GMAT-style with critical reasoning, data sufficiency and problem solving. The second part is business-case-related with multiple choices, somehow similar to the BCG potential test.