diff --git a/mailnews/local/tests/pop3/pop3Test.cpp b/mailnews/local/tests/pop3/pop3Test.cpp
index 9f96f5453f6..8a66e09e349 100644
--- a/mailnews/local/tests/pop3/pop3Test.cpp
+++ b/mailnews/local/tests/pop3/pop3Test.cpp
@@ -64,11 +64,11 @@
 #ifdef XP_MAC
 #include "nsMacRepository.h"
 #else
-#define NETLIB_DLL "libnetlib.so"
-#define XPCOM_DLL  "libxpcom.so"
-#define PREF_DLL   "libpref.so"  
-#define APPCORES_DLL "libappcores.so"
-#define APPSHELL_DLL "libnsappshell.so"
+#define NETLIB_DLL "libnetlib"MOZ_DLL_SUFFIX
+#define XPCOM_DLL  "libxpcom"MOZ_DLL_SUFFIX
+#define PREF_DLL   "libpref"MOZ_DLL_SUFFIX
+#define APPCORES_DLL "libappcores"MOZ_DLL_SUFFIX
+#define APPSHELL_DLL "libnsappshell"MOZ_DLL_SUFFIX
 #endif
 #endif
 
@@ -486,7 +486,7 @@ int main()
 	// has the ability to take nsnull as a parameter. Once that happens,
 	// prefs will do the work of figuring out which prefs file to load...
 	NS_WITH_SERVICE(nsIPref, prefs, kPrefCID, &result); 
-    if (NS_FAILED(result) || prefs == nsnull) {
+    if (NS_FAILED(result) || !prefs) {
         exit(result);
     }
     
diff --git a/mailnews/news/tests/newsParser/newsParserTest.cpp b/mailnews/news/tests/newsParser/newsParserTest.cpp
index d1adb6317db..e8158d059f0 100644
--- a/mailnews/news/tests/newsParser/newsParserTest.cpp
+++ b/mailnews/news/tests/newsParser/newsParserTest.cpp
@@ -54,10 +54,10 @@
 #ifdef XP_MAC
 #include "nsMacRepository.h"
 #else
-#define NETLIB_DLL "libnetlib.so"
-#define XPCOM_DLL  "libxpcom.so"
-#define PREF_DLL   "libpref.so"
-#define APPSHELL_DLL "libnsappshell.so"
+#define NETLIB_DLL "libnetlib"MOZ_DLL_SUFFIX
+#define XPCOM_DLL  "libxpcom"MOZ_DLL_SUFFIX
+#define PREF_DLL   "libpref"MOZ_DLL_SUFFIX
+#define APPSHELL_DLL "libnsappshell"MOZ_DLL_SUFFIX
 #endif /* XP_MAC */
 #endif /* XP_PC */
 
diff --git a/mailnews/news/tests/nntp/nntpTest.cpp b/mailnews/news/tests/nntp/nntpTest.cpp
index 47281c970e1..59115699695 100644
--- a/mailnews/news/tests/nntp/nntpTest.cpp
+++ b/mailnews/news/tests/nntp/nntpTest.cpp
@@ -66,11 +66,11 @@
 #ifdef XP_MAC
 #include "nsMacRepository.h"
 #else
-#define NETLIB_DLL "libnetlib.so"
-#define XPCOM_DLL  "libxpcom.so"
-#define NEWS_DLL   "libmsgnews.so"
-#define PREF_DLL   "libpref.so"
-#define APPSHELL_DLL "libnsappshell.so"
+#define NETLIB_DLL "libnetlib"MOZ_DLL_SUFFIX
+#define XPCOM_DLL  "libxpcom"MOZ_DLL_SUFFIX
+#define NEWS_DLL   "libmsgnews"MOZ_DLL_SUFFIX
+#define PREF_DLL   "libpref"MOZ_DLL_SUFFIX
+#define APPSHELL_DLL "libnsappshell"MOZ_DLL_SUFFIX
 #endif
 #endif