Test for implicit singleton dims with mapreducedim.

Author: maleadt

test/testsuite/mapreduce.jl

@@ -9,6 +9,10 @@ function test_mapreduce(AT)
             @test compare((A,R)->Base.mapreducedim!(x->x+x, +, R, A), AT, rand(range, sz), zeros(ET, red))
             return
         end
+
+        # implicit singleton dimensions
+        @test compare((A,R)->Base.mapreducedim!(identity, +, R, A), AT, rand(range, (2,2)), zeros(ET, (2,)))
+        @test compare((A,R)->Base.mapreducedim!(identity, +, R, A), AT, rand(range, (2,3)), zeros(ET, (2,)))
     end
     end