Index: test/Makefile
===================================================================
--- test/Makefile	(nonexistent)
+++ test/Makefile	(revision 31759)
@@ -0,0 +1,6 @@
+CFLAGS = -Wall -I.
+LDFLAGS = -lm
+main: main.o
+
+main.o: main.c ../impedance.c config.h
+
Index: test/config.h
===================================================================
--- test/config.h	(nonexistent)
+++ test/config.h	(revision 31759)
@@ -0,0 +1,4 @@
+typedef int rnd_coord_t;
+
+#define RND_COORD_TO_MM(x) ((x)/1000000)
+#define RND_MM_TO_COORD(x) ((x)*1000000)
Index: test/main.c
===================================================================
--- test/main.c	(nonexistent)
+++ test/main.c	(revision 31759)
@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include "../impedance.c"
+int main()
+{
+	double tt, th, sh, d, res;
+
+	if (scanf("%lf %lf %lf %lf", &tt, &th, &sh, &d) != 4) {
+		fprintf(stderr, "need: trace_width, trace_height, subst_height, dielect\n");
+		return 1;
+	}
+
+	res = pcb_impedance_microstrip(RND_MM_TO_COORD(tt), RND_MM_TO_COORD(th), RND_MM_TO_COORD(sh), d);
+	printf("res=%f\n", res);
+	return 0;
+}