syntax tests: add test for importing from non-existing files in libraries

Author: ogoffart

internal/compiler/tests/syntax/imports/library.slint

@@ -0,0 +1,16 @@
+// Copyright © SixtyFPS GmbH <[email protected]>
+// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
+
+import { LibraryType } from "@test-lib/lib.slint";
+
+import { NotFound } from "@not-found/foo.slint";
+//                       ^error{Cannot find requested import "@not-found/foo.slint" in the library search path}
+
+import { NotFound2 } from "@test-lib/lib.slint";
+//                        ^error{No exported type called 'NotFound2' found in "@test-lib/lib.slint"}
+import { NotFound3 } from "@test-lib/not-existing.slint";
+//                        ^error{Cannot find requested import "@test-lib/not-existing.slint" in the library search path}
+
+import { NotFound4 } from "@notexist";
+//                        ^error{Cannot find requested import "@notexist" in the library search path}
+

internal/compiler/tests/syntax_tests.rs

@@ -287,6 +287,12 @@ fn process_file_source(
     let mut compiler_config = i_slint_compiler::CompilerConfiguration::new(
         i_slint_compiler::generator::OutputFormat::Interpreter,
     );
+    compiler_config.library_paths = [(
+        "test-lib".into(),
+        concat!(env!("CARGO_MANIFEST_DIR"), "/tests/typeloader/library").into(),
+    )]
+    .into_iter()
+    .collect();
     compiler_config.embed_resources = i_slint_compiler::EmbedResourcesKind::OnlyBuiltinResources;
     compiler_config.enable_experimental = true;
     compiler_config.style = Some("fluent".into());