diff --git a/tests/test_c.c b/tests/test_c.c
index e7d892d6..49a4f98b 100644
--- a/tests/test_c.c
+++ b/tests/test_c.c
@@ -1,3 +1,4 @@
+#include <stdlib.h>
 #include <IPhreeqc.h>
 
 typedef int (*getFunc)(int);
@@ -12,65 +13,64 @@ main(int argc, const char* argv[])
   id = CreateIPhreeqc();
   if (id < 0)
   {
-    return 1;
+    return EXIT_FAILURE;
   }
 
   /* Dump */
   if (TestGetSet(id, GetDumpOn, SetDumpOn))
   {
-    return 2;
+    return EXIT_FAILURE;
   }
 
   /* Dump string */
   if (TestGetSet(id, GetDumpStringOn, SetDumpStringOn))
   {
-    return 2;
+    return EXIT_FAILURE;
   }
 
-
   /* Error */
   if (TestGetSet(id, GetErrorOn, SetErrorOn))
   {
-    return 2;
+    return EXIT_FAILURE;
   }
 
   /* Log */
   if (TestGetSet(id, GetLogOn, SetLogOn))
   {
-    return 2;
+    return EXIT_FAILURE;
   }
 
   /* Output */
   if (TestGetSet(id, GetOutputOn, SetOutputOn))
   {
-    return 2;
+    return EXIT_FAILURE;
   }
 
   /* Selected output */
   if (TestGetSet(id, GetSelectedOutputOn, SetSelectedOutputOn))
   {
-    return 2;
+    return EXIT_FAILURE;
   }
 
   if (LoadDatabase(id, "phreeqc.dat") != 0)
   {
     OutputError(id);
-    return 2;
+    return EXIT_FAILURE;
   }
 
   if (RunFile(id, "ex1") != 0)
   {
     OutputError(id);
-    return 3;
+    return EXIT_FAILURE;
   }
 
   if (DestroyIPhreeqc(id) != IPQ_OK)
   {
     OutputError(id);
-    return 4;
+    return EXIT_FAILURE;
   }
 
-  return 0;
+  return EXIT_SUCCESS;
 }
 
 int 
@@ -78,23 +78,23 @@ TestGetSet(int id, getFunc gf, setFunc sf)
 {
   if (gf(id))
   {  
-    return 2;
+    return EXIT_FAILURE;
   }
   
   if (sf(id, 1) != IPQ_OK)
   {
-    return 2;
+    return EXIT_FAILURE;
   }
   
   if (!gf(id))
   {
-    return 2;
+    return EXIT_FAILURE;
   }
   
   if (sf(id,0) != IPQ_OK)
   {
-    return 2;
+    return EXIT_FAILURE;
   }
   
-  return 0;
+  return EXIT_SUCCESS;
 }
diff --git a/tests/test_cxx.cxx b/tests/test_cxx.cxx
index e6df98a6..1cb77430 100644
--- a/tests/test_cxx.cxx
+++ b/tests/test_cxx.cxx
@@ -1,3 +1,4 @@
+#include <cstdlib>
 #include <iostream>
 #include <IPhreeqc.hpp>
 
@@ -18,17 +19,17 @@ public:
 	{
 		if ((*_p.*_get)())
 		{
-			return 2;
+			return EXIT_FAILURE;
 		}
 		(*_p.*_set)(true);
 		if (!(*_p.*_get)())
 		{
-			return 2;
+			return EXIT_FAILURE;
 		}
 		(*_p.*_set)(false);
 		if ((*_p.*_get)())
 		{
-			return 2;
+			return EXIT_FAILURE;
 		}
 		return 0;
 	}
@@ -43,55 +44,55 @@ main(int argc, const char* argv[])
   TTestGetSet<IPhreeqc> testDump(&iphreeqc, &IPhreeqc::GetDumpOn, &IPhreeqc::SetDumpOn);
   if (testDump.Test() != 0)
   {
-	  return 2;
+	  return EXIT_FAILURE;
   }
 
   // Dump string
   TTestGetSet<IPhreeqc> testDumpString(&iphreeqc, &IPhreeqc::GetDumpStringOn, &IPhreeqc::SetDumpStringOn);
   if (testDumpString.Test() != 0)
   {
-	  return 2;
+	  return EXIT_FAILURE;
   }
 
   // Error
   TTestGetSet<IPhreeqc> testError(&iphreeqc, &IPhreeqc::GetErrorOn, &IPhreeqc::SetErrorOn);
   if (testError.Test() != 0)
   {
-	  return 2;
+	  return EXIT_FAILURE;
   }
 
   // Log
   TTestGetSet<IPhreeqc> testLog(&iphreeqc, &IPhreeqc::GetLogOn, &IPhreeqc::SetLogOn);
   if (testLog.Test() != 0)
   {
-	  return 2;
+	  return EXIT_FAILURE;
   }
 
   // Output
   TTestGetSet<IPhreeqc> testOutput(&iphreeqc, &IPhreeqc::GetOutputOn, &IPhreeqc::SetOutputOn);
   if (testOutput.Test() != 0)
   {
-	  return 2;
+	  return EXIT_FAILURE;
   }
 
   // Selected output
   TTestGetSet<IPhreeqc> testSelectedOutput(&iphreeqc, &IPhreeqc::GetSelectedOutputOn, &IPhreeqc::SetSelectedOutputOn);
   if (testSelectedOutput.Test() != 0)
   {
-	  return 2;
+	  return EXIT_FAILURE;
   }
 
   if (iphreeqc.LoadDatabase("phreeqc.dat") != 0)
   {
     std::cout << iphreeqc.GetErrorString();
-    return 1;
+    return EXIT_FAILURE;
   }
 
   if (iphreeqc.RunFile("ex1") != 0)
   {
     std::cout << iphreeqc.GetErrorString();
-    return 2;
+    return EXIT_FAILURE;
   }
 
-  return 0;
+  return EXIT_SUCCESS;
 }