Added more tests for utf8

tests/it/array/utf8/mod.rs

@@ -116,6 +116,14 @@ fn not_utf8() {
     Utf8Array::<i32>::from_data(DataType::Utf8, offsets, values, None);
 }
 
+#[test]
+#[should_panic]
+fn not_utf8_individually() {
+    let offsets = Buffer::from(&[0, 1, 2]);
+    let values = Buffer::from([207, 128]); // each is invalid utf8, but together is valid
+    Utf8Array::<i32>::from_data(DataType::Utf8, offsets, values, None);
+}
+
 #[test]
 #[should_panic]
 fn wrong_offsets() {
@@ -134,37 +142,35 @@ fn wrong_data_type() {
 
 #[test]
 #[should_panic]
-fn value_with_wrong_offsets_panics() {
-    let offsets = Buffer::from(&[0, 10, 11, 4]);
+fn out_of_bounds_offsets_panics() {
+    // the 10 is out of bounds
+    let offsets = Buffer::from(&[0, 10, 11]);
     let values = Buffer::from(b"abbb");
-    // the 10-11 is not checked
-    let array = Utf8Array::<i32>::from_data(DataType::Utf8, offsets, values, None);
-
-    // but access is still checked (and panics)
-    // without checks, this would result in reading beyond bounds
-    array.value(0);
+    let _ = Utf8Array::<i32>::from_data(DataType::Utf8, offsets, values, None);
 }
 
 #[test]
 #[should_panic]
-fn index_out_of_bounds_panics() {
-    let offsets = Buffer::from(&[0, 1, 2, 4]);
+fn decreasing_offset_and_ascii_panics() {
+    let offsets = Buffer::from(&[0, 2, 1]);
     let values = Buffer::from(b"abbb");
-    let array = Utf8Array::<i32>::from_data(DataType::Utf8, offsets, values, None);
+    let _ = Utf8Array::<i32>::from_data(DataType::Utf8, offsets, values, None);
+}
 
-    array.value(3);
+#[test]
+#[should_panic]
+fn decreasing_offset_and_utf8_panics() {
+    let offsets = Buffer::from(&[0, 2, 4, 2]); // not increasing
+    let values = Buffer::from([207, 128, 207, 128, 207, 128]); // valid utf8
+    let _ = Utf8Array::<i32>::from_data(DataType::Utf8, offsets, values, None);
 }
 
 #[test]
 #[should_panic]
-fn value_unchecked_with_wrong_offsets_panics() {
-    let offsets = Buffer::from(&[0, 10, 11, 4]);
+fn index_out_of_bounds_panics() {
+    let offsets = Buffer::from(&[0, 1, 2, 4]);
     let values = Buffer::from(b"abbb");
-    // the 10-11 is not checked
     let array = Utf8Array::<i32>::from_data(DataType::Utf8, offsets, values, None);
 
-    // but access is still checked (and panics)
-    // without checks, this would result in reading beyond bounds,
-    // even if index `0` is in bounds
-    unsafe { array.value_unchecked(0) };
+    array.value(3);
 }