diff --git a/src/functional/argv.c b/src/functional/argv.c
new file mode 100644
index 0000000..487f68d
--- /dev/null
+++ b/src/functional/argv.c
@@ -0,0 +1,17 @@
+#include <limits.h>
+#include <stdio.h>
+#include "test.h"
+
+#define TEST(c, ...) \
+	( (c) || (t_error(#c " failed: " __VA_ARGS__),0) )
+
+int main(int argc, char **argv)
+{
+	char buf[PATH_MAX];
+	TEST(argc == 1, "argc should be 1\n");
+	TEST(argv[0] != 0, "argv[0] should not be NULL\n");
+	TEST(argv[1] == 0, "argv[1] should be NULL\n");
+	TEST(argv[0][0] != 0, "argv[0] should not be empty\n");
+	TEST(snprintf(buf, sizeof buf, "%s", argv[0]) < sizeof buf, "argv[0] is not a valid path\n");
+	return t_status;
+}
diff --git a/src/functional/env.c b/src/functional/env.c
index ab36381..ab1f6e4 100644
--- a/src/functional/env.c
+++ b/src/functional/env.c
@@ -14,10 +14,14 @@ int main()
 	char *s;
 	int r;
 
+	if (!environ)
+		t_error("environ is NULL\n");
 	if (clearenv() || (environ && *environ))
 		t_error("clrearenv: %s\n", strerror(errno));
 	if (putenv("TEST=1"))
 		t_error("putenv: %s\n", strerror(errno));
+	if (strcmp(environ[0],"TEST=1") != 0)
+		t_error("putenv failed: environ[0]: %s, wanted \"TEST=1\"\n", environ[0]);
 	if ((s=environ[1]))
 		t_error("environ[1]: %p, wanted 0\n", s);
 	if (!(s=getenv("TEST")))
@@ -30,21 +34,28 @@ int main()
 		t_error("*environ: %p != 0\n", s);
 	if ((s=getenv("TEST")))
 		t_error("getenv(\"TEST\"): %p, wanted 0\n", s);
+	errno = 0;
 	if (setenv("TEST", "2", 0))
 		t_error("setenv: %s\n", strerror(errno));
 	if (strcmp(s=getenv("TEST"),"2") != 0)
 		t_error("getenv(\"TEST\"): \"%s\", wanted \"2\"\n", s);
+	if (strcmp(environ[0], "TEST=2") != 0)
+		t_error("setenv failed: environ[0]: %s, wanted \"TEST=2\"\n", environ[0]);
+	errno = 0;
 	if (setenv("TEST", "3", 0))
 		t_error("setenv: %s\n", strerror(errno));
 	if (strcmp(s=getenv("TEST"),"2") != 0)
 		t_error("getenv(\"TEST\"): \"%s\", wanted \"2\"\n", s);
+	errno = 0;
 	if (setenv("TEST", "3", 1))
 		t_error("setenv: %s\n", strerror(errno));
 	if (strcmp(s=getenv("TEST"),"3") != 0)
 		t_error("getenv(\"TEST\"): \"%s\", wanted \"3\"\n", s);
 	/* test failures */
+	errno = 0;
 	if ((r=setenv("","",0)) != -1 || errno != EINVAL)
 		t_error("setenv(\"\",\"\",0): %d, errno: %d (%s), wanted -1, %d (EINVAL)\n", r, errno, strerror(errno), EINVAL);
+	errno = 0;
 	if ((r=setenv(0,"",0)) != -1 || errno != EINVAL)
 		t_error("setenv(0,\"\",0): %d, errno: %d (%s), wanted -1, %d (EINVAL)\n", r, errno, strerror(errno), EINVAL);
 	return t_status;