Shirley & Jamila Save Their Summer by Gillian Goerz

Jamila Waheed mother has her whole summer planned out, but all Jamila wants to do is play basketball. When Jamila's mother meets quirky Shirley Bones' mother at a garage sale, the two girls reluctantly come to an understanding that they hope will meet both of their needs and keep the mom's off their backs. The plan is simple: Shirley accompanies Jamila to the basketball court every day and reads while Jamila shoot baskets. Then this kid Oliver shows up begging for Shirley's help. His pet gecko has disappeared, and he's sure it was stolen. That's when Jamila discovers Shirley's secret: She's the neighborhood's best kid detective, and she's on the case. At first Jamila is put off that Shirley doesn't tell her what's going on. Then Jamila discovers she's got some detective skills of her own and a crime-solving partnership is born. All they needed was a good mystery to become best friends.