first pass of merging in warp (doesn't build)

app/src/prefix_tests.rs

@@ -0,0 +1,44 @@
+use crate::prefix::longest_common_prefix;
+
+#[test]
+fn test_basic_prefix() {
+    let strings = ["foo", "foobar", "foofoobar"];
+
+    let result = longest_common_prefix(strings);
+    assert_eq!(result.unwrap(), "foo");
+}
+
+#[test]
+fn test_no_prefix() {
+    let strings = ["foo", "foobar", "bar"];
+    let result = longest_common_prefix(strings);
+    assert_eq!(result, None);
+}
+
+#[test]
+fn test_single_string() {
+    let strings = ["foo"];
+    let result = longest_common_prefix(strings);
+    assert_eq!(result.unwrap(), "foo");
+}
+
+#[test]
+fn test_no_string() {
+    let strings = [];
+    let result = longest_common_prefix(strings);
+    assert_eq!(result, None);
+}
+
+#[test]
+fn test_multibyte_strings() {
+    let strings = ["ay東cz", "ay東ab"];
+    let result = longest_common_prefix(strings);
+    assert_eq!(result.unwrap(), "ay東");
+}
+
+#[test]
+fn test_multibyte_strings_common_bytes() {
+    let strings = ["ab東早", "ab東旪"];
+    let result = longest_common_prefix(strings);
+    assert_eq!(result.unwrap(), "ab東");
+}