Add ui tests for Panoramix derive

druid-derive/Cargo.toml

@@ -21,5 +21,6 @@ proc-macro2 = "1.0.19"
 
 [dev-dependencies]
 druid = { version = "0.7.0", path = "../druid" }
+trybuild = "1.0"
 
 float-cmp = { version = "0.8.0", features = ["std"], default-features = false }

druid-derive/tests/ui.rs

@@ -0,0 +1,21 @@
+// https://github.com/dtolnay/trybuild
+// trybuild is a crate that essentially runs cargo on the provided files, and checks the output.
+// Tests may suddenly fail after a new compiler release, and there's not much we can do about that.
+// If the test suite fails because of trybuild:
+// - Update your compiler to the latest stable version.
+// - If it still fails, update the stderr snapshots. To do so, run the test suite with
+// env variable TRYBUILD=overwrite, and submit the file changes in a PR.
+use trybuild::TestCases;
+
+#[test]
+fn ui() {
+    let t = TestCases::new();
+    t.pass("tests/ui/simple-lens.rs");
+    t.pass("tests/ui/lens-attributes.rs");
+    t.compile_fail("tests/ui/with-empty-struct.rs");
+    t.compile_fail("tests/ui/with-tuple-struct.rs");
+    t.compile_fail("tests/ui/with-enum.rs");
+    t.compile_fail("tests/ui/with-union.rs");
+
+    t.compile_fail("tests/ui/with-snake_case.rs");
+}

druid-derive/tests/ui/lens-attributes.rs

@@ -0,0 +1,20 @@
+use druid::*;
+
+#[derive(Lens)]
+struct Item {
+    #[lens(name = "count_lens")]
+    count: usize,
+    #[lens(ignore)]
+    complete: bool,
+}
+
+impl Item {
+    fn count(&self) -> usize {
+        self.count
+    }
+    fn complete(&mut self) {
+        self.complete = true;
+    }
+}
+
+fn main() {}

druid-derive/tests/ui/simple-lens.rs

@@ -0,0 +1,12 @@
+use druid::*;
+
+#[derive(Lens)]
+struct MyThing {
+    field_1: i32,
+    field_2: String,
+}
+
+fn main() {
+    let _ = MyThing::field_1;
+    let _ = MyThing::field_2;
+}

druid-derive/tests/ui/with-empty-struct.rs

@@ -0,0 +1,6 @@
+use druid::*;
+
+#[derive(Lens)]
+struct Foobar;
+
+fn main() {}

druid-derive/tests/ui/with-empty-struct.stderr

@@ -0,0 +1,5 @@
+error: Lens implementations can only be derived from structs with named fields
+ --> $DIR/with-empty-struct.rs:4:1
+  |
+4 | struct Foobar;
+  | ^^^^^^

druid-derive/tests/ui/with-enum.rs

@@ -0,0 +1,9 @@
+use druid::*;
+
+#[derive(Lens)]
+enum Foobar {
+    Foo(i32),
+    Bar,
+}
+
+fn main() {}

druid-derive/tests/ui/with-enum.stderr

@@ -0,0 +1,5 @@
+error: Lens implementations cannot be derived from enums
+ --> $DIR/with-enum.rs:4:1
+  |
+4 | enum Foobar {
+  | ^^^^

druid-derive/tests/ui/with-snake_case.rs

@@ -0,0 +1,10 @@
+#![allow(non_camel_case_types)]
+
+use druid::*;
+
+#[derive(Lens)]
+struct my_thing {
+    field: i32
+}
+
+fn main() {}

druid-derive/tests/ui/with-snake_case.stderr

@@ -0,0 +1,5 @@
+error: Lens implementations can only be derived from CamelCase types
+ --> $DIR/with-snake_case.rs:6:8
+  |
+6 | struct my_thing {
+  |        ^^^^^^^^

druid-derive/tests/ui/with-tuple-struct.rs

@@ -0,0 +1,6 @@
+use druid::*;
+
+#[derive(Lens)]
+struct Foobar(i32, i64);
+
+fn main() {}

druid-derive/tests/ui/with-tuple-struct.stderr

@@ -0,0 +1,5 @@
+error: Lens implementations can only be derived from structs with named fields
+ --> $DIR/with-tuple-struct.rs:4:1
+  |
+4 | struct Foobar(i32, i64);
+  | ^^^^^^

druid-derive/tests/ui/with-union.rs

@@ -0,0 +1,9 @@
+use druid::*;
+
+#[derive(Lens)]
+union Foobar {
+    foo: i32,
+    bar: f64,
+}
+
+fn main() {}

druid-derive/tests/ui/with-union.stderr

@@ -0,0 +1,5 @@
+error: Lens implementations cannot be derived from unions
+ --> $DIR/with-union.rs:4:1
+  |
+4 | union Foobar {
+  | ^^^^^