Rust: Add tests for Enum

Author: paldepind

rust/ql/test/library-tests/elements/enum/Cargo.lock

@@ -0,0 +1,7 @@
+fieldless
+| enums.rs:1:1:5:1 | enum Foo |
+| enums.rs:7:1:11:1 | enum Fieldless |
+| enums.rs:13:1:18:1 | enum Direction |
+unitOnly
+| enums.rs:1:1:5:1 | enum Foo |
+| enums.rs:13:1:18:1 | enum Direction |

rust/ql/test/library-tests/elements/enum/Enum.expected

@@ -0,0 +1,6 @@
+import rust
+import TestUtils
+
+query predicate fieldless(Enum e) { toBeTested(e) and e.isFieldless() }
+
+query predicate unitOnly(Enum e) { toBeTested(e) and e.isUnitOnly() }

rust/ql/test/library-tests/elements/enum/Enum.ql

@@ -0,0 +1,24 @@
+enum Foo {
+    Bar,
+    Baz,
+    Qux,
+}
+
+enum Fieldless {
+    Tuple(),
+    Struct{},
+    Unit,
+}
+
+enum Direction {
+    North = 0,
+    East = 90,
+    South = 180,
+    West = 270,
+}
+
+enum Color {
+    Red(u8),
+    Green(u8),
+    Blue(u8),
+}