1 files changed, 41 insertions, 0 deletions
diff --git a/tests/stats.awk b/tests/stats.awk
new file mode 100644
index 0000000..35142d7
--- /dev/null
+++ b/tests/stats.awk
@@ -0,0 +1,41 @@
+# read input from freq -c, check that the number of c's is approximately 10 times
+# the number of d's.
+BEGIN {
+	nc = 0
+	nd = 0
+		# number of c's and d's
+	epsilon = 0.10
+		# acceptable error between nc and 10*nd
+}
+/^c/ { nc = $2 }
+/^d/ { nd = $2 }
+END {
+	if (nc == 0) {
+		print "stats.awk: no c's"
+		exit 1
+	} else if (nd == 0) {
+		print "stats.awk: no d's"
+		exit 1
+	}
+	diff = percdiff(nc, 10*nd)
+	if (diff > epsilon) {
+		printf "difference between the number of c's (%d) and 10 times the number of d's (10*%d=%d)is too great (%.1f%% > %.1f%%)\n",
+			nc, nd, 10*nd, diff*100, epsilon*100
+		exit 1
+	}
+}
+
+# percdiff: percent difference between a and b
+function percdiff(a, b) {
+	return abs(a - b) / avg(a, b)
+}
+
+function abs(x) {
+	if (x < 0)
+		return -x
+	return x
+}
+
+function avg(a, b) {
+	return (a + b) / 2
+}
+\ No newline at end of file