diff --git a/t/02_exit.t b/t/02_exit.t
index 6bb3dd3..254019d 100644
--- a/t/02_exit.t
+++ b/t/02_exit.t
@@ -15,6 +15,11 @@ if ($^O ne 'VMS') {
 use IPC::System::Simple qw(run EXIT_ANY);
 chdir("t");	# Ignore return, since we may already be in t/
 
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 run($perl_path,"exiter.pl",0);
 ok(1,"Multi-arg implicit zero allowed");
 
diff --git a/t/03_signal.t b/t/03_signal.t
index 8cf07e1..f5c3ef7 100644
--- a/t/03_signal.t
+++ b/t/03_signal.t
@@ -24,6 +24,11 @@ use_ok("IPC::System::Simple","run");
 
 chdir("t");
 
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 run([1],$perl_path,"signaler.pl",0);
 ok(1);
 
diff --git a/t/04_capture.t b/t/04_capture.t
index 6a75a7a..32ec00d 100644
--- a/t/04_capture.t
+++ b/t/04_capture.t
@@ -20,6 +20,11 @@ my $output_exe = "$perl_path output.pl";
 use_ok("IPC::System::Simple","capture");
 chdir("t");
 
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 # Scalar capture
 
 my $output = capture($output_exe);
diff --git a/t/05_multi_capture.t b/t/05_multi_capture.t
index ce7ad62..d6f2325 100644
--- a/t/05_multi_capture.t
+++ b/t/05_multi_capture.t
@@ -19,6 +19,11 @@ if ($^O ne 'VMS') {
 use_ok("IPC::System::Simple","capture");
 chdir("t");
 
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 # The tests below for $/ are left in, even though IPC::System::Simple
 # never touches $/
 
diff --git a/t/07_taint.t b/t/07_taint.t
index b16ef8e..35a4ae0 100644
--- a/t/07_taint.t
+++ b/t/07_taint.t
@@ -17,6 +17,11 @@ use_ok("IPC::System::Simple","run","capture");
 
 chdir("t");     # Ignore return, since we may already be in t/
 
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 my $taint = $0 . "foo";	# ."foo" to avoid zero length
 ok(tainted($taint),"Sanity - executable name is tainted");
 
diff --git a/t/08_core.t b/t/08_core.t
index 221f133..871aebb 100644
--- a/t/08_core.t
+++ b/t/08_core.t
@@ -36,6 +36,11 @@ use_ok("IPC::System::Simple","run");
 
 chdir("t");
 
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 my $rlimit_success = setrlimit(RLIMIT_CORE, RLIM_INFINITY, RLIM_INFINITY);
 
 SKIP: {
diff --git a/t/09_system.t b/t/09_system.t
index 77c7d51..e5955b6 100644
--- a/t/09_system.t
+++ b/t/09_system.t
@@ -15,6 +15,11 @@ if ($^O ne 'VMS') {
 use IPC::System::Simple qw(system);
 chdir("t");	# Ignore return, since we may already be in t/
 
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 system($perl_path,"exiter.pl",0);
 ok(1,"Multi-arg system");
 
diff --git a/t/11_newlines.t b/t/11_newlines.t
index 9f40aa5..d0cec9c 100644
--- a/t/11_newlines.t
+++ b/t/11_newlines.t
@@ -11,6 +11,12 @@ if ($^O ne 'VMS') {
         unless $perl_path =~ m/$Config{_exe}$/i;
 }
 
+chdir("t");	# Ignore return, since we may already be in t/
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 eval { run( "$perl_path -e1" ) };
 is($@, "", 'Run works with single arg');
 
diff --git a/t/12_systemx.t b/t/12_systemx.t
index 6d08e4b..a4a04eb 100644
--- a/t/12_systemx.t
+++ b/t/12_systemx.t
@@ -14,6 +14,11 @@ if ($^O ne 'VMS') {
 
 chdir("t");     # Ignore return, since we may already be in t/
 
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 my $exit_test = "$perl_path exiter.pl 0";
 
 eval {
diff --git a/t/win32.t b/t/win32.t
index eee596d..13208b4 100644
--- a/t/win32.t
+++ b/t/win32.t
@@ -40,6 +40,11 @@ ok($raw_perl, "Have perl executables with and w/o extensions.");
 
 chdir("t");
 
+#Close STDIN (and reopen to prevent warnings)
+#If Perl is called with no arguments, it waits for input on STDIN.
+close STDIN;
+open STDIN, '<', '/dev/null';
+
 # Check for 16 and 32 bit returns.
 
 foreach my $big_exitval (SMALL_EXIT, BIG_EXIT, HUGE_EXIT) {