diff --git a/tests/AdventOfCodeFPCUnit.lpi b/tests/AdventOfCodeFPCUnit.lpi
index 4b3c50c..fff5ccd 100644
--- a/tests/AdventOfCodeFPCUnit.lpi
+++ b/tests/AdventOfCodeFPCUnit.lpi
@@ -44,6 +44,10 @@
         <Filename Value="..\USolver.pas"/>
         <IsPartOfProject Value="True"/>
       </Unit>
+      <Unit>
+        <Filename Value="UBaseTestCases.pas"/>
+        <IsPartOfProject Value="True"/>
+      </Unit>
     </Units>
   </ProjectOptions>
   <CompilerOptions>
diff --git a/tests/AdventOfCodeFPCUnit.lpr b/tests/AdventOfCodeFPCUnit.lpr
index 6ba23fb..cb55c7b 100644
--- a/tests/AdventOfCodeFPCUnit.lpr
+++ b/tests/AdventOfCodeFPCUnit.lpr
@@ -3,7 +3,7 @@ program AdventOfCodeFPCUnit;
 {$mode objfpc}{$H+}
 
 uses
-  Interfaces, Forms, GuiTestRunner, UGearRatiosTestCases, USolver;
+  Interfaces, Forms, GuiTestRunner, USolver, UBaseTestCases, UGearRatiosTestCases;
 
 {$R *.res}
 
diff --git a/tests/UBaseTestCases.pas b/tests/UBaseTestCases.pas
new file mode 100644
index 0000000..57c8651
--- /dev/null
+++ b/tests/UBaseTestCases.pas
@@ -0,0 +1,57 @@
+{
+  Solutions to the Advent Of Code.
+  Copyright (C) 2023  Stefan Müller
+
+  This program is free software: you can redistribute it and/or modify it under
+  the terms of the GNU General Public License as published by the Free Software
+  Foundation, either version 3 of the License, or (at your option) any later
+  version.
+
+  This program is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  this program.  If not, see <http://www.gnu.org/licenses/>.
+}
+
+unit UBaseTestCases;
+
+{$mode ObjFPC}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils, fpcunit, USolver;
+
+type
+
+  { TBaseTestCase }
+
+  TBaseTestCase = class(TTestCase)
+  protected
+    FEngine: TSolverEngine;
+    FSolver: ISolver;
+    procedure Setup; override;
+    procedure TearDown; override;
+  end;
+
+implementation
+
+{ TBaseTestCase }
+
+procedure TBaseTestCase.Setup;
+begin
+  inherited Setup;
+  FEngine := TSolverEngine.Create(ConcatPaths(['..', '..', 'bin', 'data']));
+end;
+
+procedure TBaseTestCase.TearDown;
+begin
+  FSolver.Free;
+  FEngine.Free;
+  inherited TearDown;
+end;
+
+end.
+
diff --git a/tests/UGearRatiosTestCases.pas b/tests/UGearRatiosTestCases.pas
index 6568d86..1aa23a9 100644
--- a/tests/UGearRatiosTestCases.pas
+++ b/tests/UGearRatiosTestCases.pas
@@ -22,38 +22,27 @@ unit UGearRatiosTestCases;
 interface
 
 uses
-  Classes, SysUtils, fpcunit, testregistry, USolver, UGearRatios;
+  Classes, SysUtils, fpcunit, testregistry, USolver, UBaseTestCases, UGearRatios;
 
 type
 
   { TGearRatiosBaseTestCase }
 
-  TGearRatiosBaseTestCase = class(TTestCase)
+  TGearRatiosBaseTestCase = class(TBaseTestCase)
   protected
-    FSolver: TGearRatios;
     procedure Setup; override;
-    procedure TearDown; override;
   end;
 
   { TGearRatiosFullDataTestCase }
 
   TGearRatiosFullDataTestCase = class(TGearRatiosBaseTestCase)
   protected
-    FEngine: TSolverEngine;
     procedure Setup; override;
-    procedure TearDown; override;
   published
     procedure TestPart1;
     procedure TestPart2;
   end;
 
-  { TGearRatiosTestCase }
-
-  TGearRatiosTestCase = class(TGearRatiosBaseTestCase)
-  published
-    procedure TestEndOfLineNumber;
-  end;
-
   { TGearRatiosExampleTestCase }
 
   TGearRatiosExampleTestCase = class(TGearRatiosBaseTestCase)
@@ -64,35 +53,31 @@ type
     procedure TestPart2;
   end;
 
+  { TGearRatiosTestCase }
+
+  TGearRatiosTestCase = class(TGearRatiosBaseTestCase)
+  published
+    procedure TestEndOfLineNumber;
+  end;
+
 implementation
 
 { TGearRatiosBaseTestCase }
 
 procedure TGearRatiosBaseTestCase.Setup;
 begin
+  inherited Setup;
   FSolver := TGearRatios.Create;
 end;
 
-procedure TGearRatiosBaseTestCase.TearDown;
-begin
-  FSolver.Free;
-end;
-
 { TGearRatiosFullDataTestCase }
 
 procedure TGearRatiosFullDataTestCase.Setup;
 begin
   inherited Setup;
-  FEngine := TSolverEngine.Create(ConcatPaths(['..', '..', 'bin', 'data']));
   FEngine.ProcessData(FSolver);
 end;
 
-procedure TGearRatiosFullDataTestCase.TearDown;
-begin
-  FEngine.Free;
-  inherited TearDown;
-end;
-
 procedure TGearRatiosFullDataTestCase.TestPart1;
 begin
   AssertEquals(530495, FSolver.GetResultPart1);
@@ -103,17 +88,6 @@ begin
   AssertEquals(80253814, FSolver.GetResultPart2);
 end;
 
-
-{ TGearRatiosTestCase }
-
-procedure TGearRatiosTestCase.TestEndOfLineNumber;
-begin
-  FSolver.Init;
-  FSolver.ProcessDataLine('...$541');
-  FSolver.Finish;
-  AssertEquals('Result of part 1 calculation incorrect.', 541, FSolver.GetResultPart1);
-end;
-
 { TGearRatiosExampleTestCase }
 
 procedure TGearRatiosExampleTestCase.Setup;
@@ -143,9 +117,19 @@ begin
   AssertEquals(467835, FSolver.GetResultPart2);
 end;
 
+{ TGearRatiosTestCase }
+
+procedure TGearRatiosTestCase.TestEndOfLineNumber;
+begin
+  FSolver.Init;
+  FSolver.ProcessDataLine('...$541');
+  FSolver.Finish;
+  AssertEquals('Result of part 1 calculation incorrect.', 541, FSolver.GetResultPart1);
+end;
+
 initialization
 
   RegisterTest(TGearRatiosFullDataTestCase);
-  RegisterTest(TGearRatiosTestCase);
   RegisterTest(TGearRatiosExampleTestCase);
+  RegisterTest(TGearRatiosTestCase);
 end.
diff --git a/tests/bin/AdventOfCodeFPCUnit.fpcunit.ini b/tests/bin/AdventOfCodeFPCUnit.fpcunit.ini
index c7501c6..87cc773 100644
--- a/tests/bin/AdventOfCodeFPCUnit.fpcunit.ini
+++ b/tests/bin/AdventOfCodeFPCUnit.fpcunit.ini
@@ -8,18 +8,18 @@ Height=663
 All Tests.Checked=1
 All Tests.Expanded=1
 TGearRatiosFullDataTestCase.Checked=1
-TGearRatiosFullDataTestCase.Expanded=1
+TGearRatiosFullDataTestCase.Expanded=0
 TGearRatiosFullDataTestCase.TestPart1.Checked=1
 TGearRatiosFullDataTestCase.TestPart1.Expanded=0
 TGearRatiosFullDataTestCase.TestPart2.Checked=1
 TGearRatiosFullDataTestCase.TestPart2.Expanded=0
-TGearRatiosTestCase.Checked=1
-TGearRatiosTestCase.Expanded=1
-TGearRatiosTestCase.TestEndOfLineNumber.Checked=1
-TGearRatiosTestCase.TestEndOfLineNumber.Expanded=0
 TGearRatiosExampleTestCase.Checked=1
-TGearRatiosExampleTestCase.Expanded=1
+TGearRatiosExampleTestCase.Expanded=0
 TGearRatiosExampleTestCase.TestPart1.Checked=1
 TGearRatiosExampleTestCase.TestPart1.Expanded=0
 TGearRatiosExampleTestCase.TestPart2.Checked=1
 TGearRatiosExampleTestCase.TestPart2.Expanded=0
+TGearRatiosTestCase.Checked=1
+TGearRatiosTestCase.Expanded=0
+TGearRatiosTestCase.TestEndOfLineNumber.Checked=1
+TGearRatiosTestCase.TestEndOfLineNumber.Expanded=0