diff --git a/algs4/src/meatballhat.com/algs4/binarysearch_test.go b/algs4/src/meatballhat.com/algs4/binarysearch_test.go
new file mode 100644
index 0000000..92412eb
--- /dev/null
+++ b/algs4/src/meatballhat.com/algs4/binarysearch_test.go
@@ -0,0 +1,21 @@
+package algs4_test
+
+import (
+	"testing"
+)
+
+import (
+	"meatballhat.com/algs4"
+)
+
+func TestBinarySearchRank(t *testing.T) {
+	arr := [...]int{0, 2, 9, 14, 23}
+
+	if algs4.BinarySearchRank(9, arr[:]) != 2 {
+		t.Error("Failed to find 9 in", arr)
+	}
+
+	if algs4.BinarySearchRank(0, arr[:]) != 0 {
+		t.Error("Failed to find 0 in", arr)
+	}
+}