zstring_view: Fix find functions

Change-Id: I5a3765f1a29531435fea49930c84890969f5dd8b
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/test/zstring_view.cpp b/test/zstring_view.cpp
index 14a1e04..40ad4d4 100644
--- a/test/zstring_view.cpp
+++ b/test/zstring_view.cpp
@@ -30,6 +30,10 @@
     char mut[] = "aa";
     auto s3 = zstring_view(mut);
 
+    EXPECT_EQ(1, s1.find('c'));
+    EXPECT_EQ(0, s3.find('a'));
+    EXPECT_EQ(1, s3.rfind('a'));
+
     EXPECT_NE(sv, s2);
     EXPECT_NE(s1, s2);
     EXPECT_EQ(s3, "aa");