diff --git a/test/runtests.jl b/test/runtests.jl
index b41305a..114b1ad 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -4,128 +4,43 @@ using Test
 
 
 @testset "AtomicAndPhysicalConstants.jl" begin
-    # Write your tests here.
+  # Write your tests here.
 end
 
-@testset "set_units.jl" begin
-
-    # units should be available to users, including "amu" and "e"
-    # if not availble, an error would be thrown and the test would fail.
-    @test u"kg" == u"kg"
-    @test u"km" == u"km"
-    @test u"amu" == u"amu"
-    @test u"eV/c^2" == u"eV/c^2"
-    @test u"e" == u"e"
-    @test u"C" == u"C"
-    @test u"s" == u"s"
-
-
-    #setunits to default units
-    setunits()
-
-    #when setunits is runned all constants should be initialized to default units
-
-    @test m_electron ≈ 0.51099895000e6
-    @test m_proton ≈ 0.93827208816e9
-    @test m_neutron ≈ 0.93956542052e9
-    @test m_muon ≈ 105.6583755e6
-    @test m_helion ≈ 2.808391607035771e9
-    @test m_deuteron ≈ 1.87561294257e9
-
-    @test c_light ≈ 2.99792458e8
-    @test e_charge ≈ 1
-    @test r_e ≈ 2.8179403262e-15
-    @test h_planck ≈ 4.135667696e-15
-    @test mu_0_vac ≈ 1.25663706212e-6
-    @test eps_0_vac ≈ 8.854187812800385e-12
-
-
-    @test kg_per_amu ≈ 1.66053906660e-27
-    @test eV_per_amu ≈ 9.3149410242e8
-    @test N_avogadro ≈ 6.02214076e23
-    @test fine_structure ≈ 7.2973525693e-3
-
-    @test classical_radius_factor ≈ 1.4399645478508574e-9
-    @test r_p ≈ 1.5346982671888946e-18
-    @test h_bar_planck ≈ 6.582119568038699e-16
-    @test kg_per_eV ≈ 1.7826619216224324e-36
-
-    #set units to MKS
-    setunits(MKS)
-
-    #mass should have unit in kg instead of eV/c^2
-    @test m_electron ≈ 9.109383701540453e-31
-    @test m_proton ≈ 1.6726219236839978e-27
-    @test m_neutron ≈ 1.674927498034172e-27
-    @test m_muon ≈ 1.8835316270433453e-28
-    @test m_helion ≈ 5.006412778866699e-27
-    @test m_deuteron ≈ 3.3435837724217406e-27
-
-    #c_light shouldn't change
-    @test c_light ≈ 2.99792458e8
-
-    #e_charge should be in Coulomb 
-    @test e_charge ≈ 1.602176634e-19
-
-    #unitless constants shouldn't change
-
-
-    @test kg_per_amu ≈ 1.66053906660e-27
-    @test eV_per_amu ≈ 9.3149410242e8
-    @test N_avogadro ≈ 6.02214076e23
-    @test fine_structure ≈ 7.2973525693e-3
-
-    #set units to MKS and mass to MeV, and mass should have unit in MeV/c^2
-    setunits(MKS, mass_unit="MeV/c^2")
-
-    @test m_electron ≈ 0.51099895000e6 / 10^6
-    @test m_proton ≈ 0.93827208816e9 / 10^6
-    @test m_neutron ≈ 0.93956542052e9 / 10^6
-    @test m_muon ≈ 105.6583755e6 / 10^6
-    @test m_helion ≈ 2.808391607035771e9 / 10^6
-    @test m_deuteron ≈ 1.87561294257e9 / 10^6
-
-    #set the unit of time to hour, the unit of speed should be m/hour
-    setunits(time_unit="hr")
-
-    @test c_light ≈ 2.99792458e8 * 3600
-
-    # set units to CGS, the speed should be in cm/s, and mass should be in gram
-    setunits(CGS)
-
-    @test c_light ≈ 2.99792458e10
-
-    @test m_electron ≈ 9.109383701540453e-28
-    @test m_proton ≈ 1.6726219236839978e-24
-    @test m_neutron ≈ 1.674927498034172e-24
-    @test m_muon ≈ 1.8835316270433453e-25
-    @test m_helion ≈ 5.006412778866699e-24
-    @test m_deuteron ≈ 3.3435837724217406e-24
-
-    #if unit has the wrong dimension exist a MethodError will be thrown
-    @test_throws ErrorException setunits(mass_unit="km")
-    @test_throws ErrorException setunits(charge_unit="eV/c^2")
-    @test_throws ErrorException setunits(time_unit="J/km")
-
-
-
-    #test massof and chargeof
-
-    #create some particles
-
-    H = Species("H")
-
-    #mass should be in amu and charge in elementary charge
-    setunits(mass_unit=u"eV/c^2")
-
-    # @test mass(H) ≈ 1.000 atol = 1e-4
-    # @test charge(H) ≈ 1
-    @test mass(H, "kg") ≈ 1.6605e-27 atol = 1e-27
-
-		# since Species("H") yields a neutral atom, the following test is wrong
-    # @test charge(H, "C") ≈ 1.6021e-19 atol = 1e-19
-
-    s = Species("electron")
-    @test mass(s, u"eV/c^2") ≈ 510998.95069 atol = 1
+# test default APCdef settings
+@APCdef
+
+@testset "testAPCdef" begin
+  #constants should be of type float in the right unit
+  @test C_LIGHT ≈ 2.99792458e8
+  @test H_PLANCK ≈ 4.135667696e-15
+  @test H_BAR_PLANCK ≈ 6.582119568038699e-16
+  @test R_E ≈ 2.8179403205e-15
+  @test R_P ≈ 1.5346982640795807e-12
+  @test E_CHARGE ≈ 1
+  @test MU_0_VAC ≈ 1.25663706127e-6
+  @test EPS_0_VAC ≈ 8.8541878188e-12
+  @test CLASSICAL_RADIUS_FACTOR ≈ 1.4399645468825422e-15
+  @test FINE_STRUCTURE ≈ 0.0072973525643
+  @test N_AVOGADRO ≈ 6.02214076e23
+
+  #test massof() and chargeof()
+  H = Species("H")
+
+  @test massof(H) ≈ 9.394018682512946e8
+  @test chargeof(H) ≈ 0
+
+  e = Species("electron")
+  @test massof(e) ≈ 510998.95069
+  @test chargeof(e) ≈ -1
+end
 
+@testset "testSpecies" begin
+  #test '+' and '-' signs to charge
+  @test chargeof(Species("H+")) ≈ 1
+  @test chargeof(Species("Mg++")) ≈ 2
+  @test chargeof(Species("Al+3")) ≈ 3
+  @test chargeof(Species("Cl-")) ≈ -1
+  @test chargeof(Species("O--")) ≈ -2
+  @test chargeof(Species("N-3")) ≈ -3
 end
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