diff --git a/src/Electrical/Analog/transistors.jl b/src/Electrical/Analog/transistors.jl
index 0af2bd13..129e8f3a 100644
--- a/src/Electrical/Analog/transistors.jl
+++ b/src/Electrical/Analog/transistors.jl
@@ -164,7 +164,6 @@ Early voltage effect.
     end
 end
 
-
 """
     PNP(;name, B_F, B_R, Is, V_T, V_A, phi_C, phi_E, Z_C, Z_E, Tau_f, Tau_r, C_jC0, C_jE0, C_CS, gamma_C, gamma_E, NF, NR)
 
@@ -329,4 +328,4 @@ Early voltage effect.
         b.i ~ -IEC / B_R - ICC / B_F - (C_jC + C_DC) * D(V_CB) - (C_jE + C_DE) * D(V_EB)
         e.i ~ -c.i - b.i - I_sub
     end
-end
\ No newline at end of file
+end
diff --git a/src/Hydraulic/IsothermalCompressible/components.jl b/src/Hydraulic/IsothermalCompressible/components.jl
index 5815f9c9..2921cc28 100644
--- a/src/Hydraulic/IsothermalCompressible/components.jl
+++ b/src/Hydraulic/IsothermalCompressible/components.jl
@@ -354,7 +354,7 @@ end
         vol(t)
     end
 
-  # let
+    # let
     dm = port.dm
     p = port.p
 
@@ -454,7 +454,6 @@ See also [`FixedVolume`](@ref), [`DynamicVolume`](@ref)
         direction = +1,
         x_int,
         name)
-
     pars = @parameters begin
         area = area
         x_int = x_int
@@ -489,11 +488,11 @@ See also [`FixedVolume`](@ref), [`DynamicVolume`](@ref)
     end
 
     eqs = [
-            # connectors
-            port.p ~ p
-            port.dm ~ dm
-            flange.v * direction ~ dx
-            flange.f * direction ~ -f
+           # connectors
+           port.p ~ p
+           port.dm ~ dm
+           flange.v * direction ~ dx
+           flange.f * direction ~ -f
            # differentials
            D(x) ~ dx
            D(m) ~ dm
diff --git a/test/Electrical/analog.jl b/test/Electrical/analog.jl
index b3f96515..1fcc02e4 100644
--- a/test/Electrical/analog.jl
+++ b/test/Electrical/analog.jl
@@ -541,9 +541,7 @@ end
     # savefig(plt, "rc_circuit_test_variable_resistor")
 end
 
-
 @testset "NPN Tests" begin
-
     @mtkmodel SimpleNPNCircuit begin
         @components begin
             Q1 = NPN()
@@ -624,10 +622,8 @@ end
         sol[sys.Q1.c.i][15] +
         sol[sys.Q1.s.i][15],
         0.0, atol = 1e-16)
-
 end
 
-
 @testset "PNP Tests" begin
     @mtkmodel SimplePNPCircuit begin
         @components begin
@@ -710,4 +706,4 @@ end
         sol[sys.Q1.s.i][15],
         0.0,
         atol = 1e-16)
-end
\ No newline at end of file
+end
diff --git a/test/Thermal/piston.jl b/test/Thermal/piston.jl
index 9b915f71..03e42ff6 100644
--- a/test/Thermal/piston.jl
+++ b/test/Thermal/piston.jl
@@ -41,8 +41,6 @@ using ModelingToolkitStandardLibrary.Blocks
     @test SciMLBase.successful_retcode(sol)
     # The initial value doesn't add up to absolute zero, while the rest do. To avoid
     # tolerance on the latter, the test is split in two parts.
-    @test sol[piston.gas.Q_flow][1] + sol[piston.coolant.Q_flow][1]≈0 atol=1e-6
-    @test sol[piston.gas.Q_flow][2:end] +
-          sol[piston.coolant.Q_flow][2:end]≈
-    zeros(length(sol) - 1) atol=1e-6
+    @test sol[piston.gas.Q_flow][1]≈-sol[piston.coolant.Q_flow][1] rtol=1e-6
+    @test sol[piston.gas.Q_flow][2:end]≈-sol[piston.coolant.Q_flow][2:end] rtol=1e-6
 end