fix typo

Author: ytdHuang

test/core-test/quantum_objects_evo.jl

@@ -107,7 +107,7 @@
         H_isconst = isconstant(H)
         H_elements = 2
         @test opstring ==
-              "Quantum Object Evo.:   type=Operator   dims=$H_dims   size=$H_size   ishermitian=$H_isherm   isconstant=$H_isconst   num_elements=$$H_elements\n$datastring"
+              "Quantum Object Evo.:   type=Operator   dims=$H_dims   size=$H_size   ishermitian=$H_isherm   isconstant=$H_isconst   num_elements=$H_elements\n$datastring"
 
         L = QobjEvo(spre(a))
         opstring = sprint((t, s) -> show(t, "text/plain", s), L)
@@ -118,7 +118,7 @@
         L_isconst = isconstant(L)
         H_elements = 1
         @test opstring ==
-              "Quantum Object Evo.:   type=SuperOperator   dims=$L_dims   size=$L_size   ishermitian=$L_isherm   isconstant=$L_isconst   num_elements=$$L_elements\n$datastring"
+              "Quantum Object Evo.:   type=SuperOperator   dims=$L_dims   size=$L_size   ishermitian=$L_isherm   isconstant=$L_isconst   num_elements=$L_elements\n$datastring"
     end
 
     @testset "Type Inference (QuantumObject)" begin