Fix problem with deque clear!

Author: Koustav Chowdhury

src/deque.jl

@@ -38,6 +38,8 @@ isrear(blk::DequeBlock) =  blk.next === blk
 # reset the block to empty, and position
 
 function reset!(blk::DequeBlock{T}, front::Int) where T
+    empty!(blk.data)
+    blk.data = Vector{T}(undef, blk.capa)
     blk.front = front
     blk.back = front - 1
     blk.prev = blk

test/test_deque.jl

@@ -196,5 +196,20 @@
         @test length(sprint(dump,q)) >= 0
         @test typeof(empty!(q)) === typeof(Deque{Int}())
         @test isempty(q)
+        @test num_blocks(q) == 1
+        @test q.head === q.rear
+        @test sizeof(q.head.data) == q.head.capa * sizeof(eltype(q))
+    end
+
+    @testset "push! after empty!" begin
+        q = Deque{Int}(1)
+        push!(q,1)
+        push!(q,2)
+        empty!(q)
+        push!(q,3)
+        @test length(q) == 1
+        @test first(q) == 3
+        @test last(q) == 3
+        @test num_blocks(q) == 1
     end
 end # @testset Deque