testjobqueue: initialize dependants map

Adding to a nil map leads to panic. We must ensure that all maps are
initialized before use.

Signed-off-by: Tom Gundersen <teg@jklm.no>

internal/jobqueue/testjobqueue/testjobqueue.go

@@ -38,8 +38,9 @@ type job struct {
 
 func New() *testJobQueue {
 	return &testJobQueue{
-		jobs:    make(map[uuid.UUID]*job),
-		pending: make(map[string][]uuid.UUID),
+		jobs:       make(map[uuid.UUID]*job),
+		pending:    make(map[string][]uuid.UUID),
+		dependants: make(map[uuid.UUID][]uuid.UUID),
 	}
 }