1 files changed, 228 insertions, 0 deletions

diff --git a/crates/base_db/src/fixture.rs b/crates/base_db/src/fixture.rs
new file mode 100644
index 000000000..5ff8ead0e
--- /dev/null
+++ b/crates/base_db/src/fixture.rs
@@ -0,0 +1,228 @@
+//! Fixtures are strings containing rust source code with optional metadata.
+//! A fixture without metadata is parsed into a single source file.
+//! Use this to test functionality local to one file.
+//!
+//! Simple Example:
+//! ```
+//! r#"
+//! fn main() {
+//!     println!("Hello World")
+//! }
+//! "#
+//! ```
+//!
+//! Metadata can be added to a fixture after a `//-` comment.
+//! The basic form is specifying filenames,
+//! which is also how to define multiple files in a single test fixture
+//!
+//! Example using two files in the same crate:
+//! ```
+//! "
+//! //- /main.rs
+//! mod foo;
+//! fn main() {
+//!     foo::bar();
+//! }
+//!
+//! //- /foo.rs
+//! pub fn bar() {}
+//! "
+//! ```
+//!
+//! Example using two crates with one file each, with one crate depending on the other:
+//! ```
+//! r#"
+//! //- /main.rs crate:a deps:b
+//! fn main() {
+//!     b::foo();
+//! }
+//! //- /lib.rs crate:b
+//! pub fn b() {
+//!     println!("Hello World")
+//! }
+//! "#
+//! ```
+//!
+//! Metadata allows specifying all settings and variables
+//! that are available in a real rust project:
+//! - crate names via `crate:cratename`
+//! - dependencies via `deps:dep1,dep2`
+//! - configuration settings via `cfg:dbg=false,opt_level=2`
+//! - environment variables via `env:PATH=/bin,RUST_LOG=debug`
+//!
+//! Example using all available metadata:
+//! ```
+//! "
+//! //- /lib.rs crate:foo deps:bar,baz cfg:foo=a,bar=b env:OUTDIR=path/to,OTHER=foo
+//! fn insert_source_code_here() {}
+//! "
+//! ```
+use std::{str::FromStr, sync::Arc};
+
+use cfg::CfgOptions;
+use rustc_hash::FxHashMap;
+use test_utils::{extract_range_or_offset, Fixture, RangeOrOffset, CURSOR_MARKER};
+use vfs::{file_set::FileSet, VfsPath};
+
+use crate::{
+    input::CrateName, CrateGraph, CrateId, Edition, Env, FileId, FilePosition, SourceDatabaseExt,
+    SourceRoot, SourceRootId,
+};
+
+pub const WORKSPACE: SourceRootId = SourceRootId(0);
+
+pub trait WithFixture: Default + SourceDatabaseExt + 'static {
+    fn with_single_file(text: &str) -> (Self, FileId) {
+        let mut db = Self::default();
+        let (_, files) = with_files(&mut db, text);
+        assert_eq!(files.len(), 1);
+        (db, files[0])
+    }
+
+    fn with_files(ra_fixture: &str) -> Self {
+        let mut db = Self::default();
+        let (pos, _) = with_files(&mut db, ra_fixture);
+        assert!(pos.is_none());
+        db
+    }
+
+    fn with_position(ra_fixture: &str) -> (Self, FilePosition) {
+        let (db, file_id, range_or_offset) = Self::with_range_or_offset(ra_fixture);
+        let offset = match range_or_offset {
+            RangeOrOffset::Range(_) => panic!(),
+            RangeOrOffset::Offset(it) => it,
+        };
+        (db, FilePosition { file_id, offset })
+    }
+
+    fn with_range_or_offset(ra_fixture: &str) -> (Self, FileId, RangeOrOffset) {
+        let mut db = Self::default();
+        let (pos, _) = with_files(&mut db, ra_fixture);
+        let (file_id, range_or_offset) = pos.unwrap();
+        (db, file_id, range_or_offset)
+    }
+
+    fn test_crate(&self) -> CrateId {
+        let crate_graph = self.crate_graph();
+        let mut it = crate_graph.iter();
+        let res = it.next().unwrap();
+        assert!(it.next().is_none());
+        res
+    }
+}
+
+impl<DB: SourceDatabaseExt + Default + 'static> WithFixture for DB {}
+
+fn with_files(
+    db: &mut dyn SourceDatabaseExt,
+    fixture: &str,
+) -> (Option<(FileId, RangeOrOffset)>, Vec<FileId>) {
+    let fixture = Fixture::parse(fixture);
+
+    let mut files = Vec::new();
+    let mut crate_graph = CrateGraph::default();
+    let mut crates = FxHashMap::default();
+    let mut crate_deps = Vec::new();
+    let mut default_crate_root: Option<FileId> = None;
+
+    let mut file_set = FileSet::default();
+    let source_root_id = WORKSPACE;
+    let source_root_prefix = "/".to_string();
+    let mut file_id = FileId(0);
+
+    let mut file_position = None;
+
+    for entry in fixture {
+        let text = if entry.text.contains(CURSOR_MARKER) {
+            let (range_or_offset, text) = extract_range_or_offset(&entry.text);
+            assert!(file_position.is_none());
+            file_position = Some((file_id, range_or_offset));
+            text.to_string()
+        } else {
+            entry.text.clone()
+        };
+
+        let meta = FileMeta::from(entry);
+        assert!(meta.path.starts_with(&source_root_prefix));
+
+        if let Some(krate) = meta.krate {
+            let crate_id = crate_graph.add_crate_root(
+                file_id,
+                meta.edition,
+                Some(krate.clone()),
+                meta.cfg,
+                meta.env,
+                Default::default(),
+            );
+            let crate_name = CrateName::new(&krate).unwrap();
+            let prev = crates.insert(crate_name.clone(), crate_id);
+            assert!(prev.is_none());
+            for dep in meta.deps {
+                let dep = CrateName::new(&dep).unwrap();
+                crate_deps.push((crate_name.clone(), dep))
+            }
+        } else if meta.path == "/main.rs" || meta.path == "/lib.rs" {
+            assert!(default_crate_root.is_none());
+            default_crate_root = Some(file_id);
+        }
+
+        db.set_file_text(file_id, Arc::new(text));
+        db.set_file_source_root(file_id, source_root_id);
+        let path = VfsPath::new_virtual_path(meta.path);
+        file_set.insert(file_id, path.into());
+        files.push(file_id);
+        file_id.0 += 1;
+    }
+
+    if crates.is_empty() {
+        let crate_root = default_crate_root.unwrap();
+        crate_graph.add_crate_root(
+            crate_root,
+            Edition::Edition2018,
+            None,
+            CfgOptions::default(),
+            Env::default(),
+            Default::default(),
+        );
+    } else {
+        for (from, to) in crate_deps {
+            let from_id = crates[&from];
+            let to_id = crates[&to];
+            crate_graph.add_dep(from_id, CrateName::new(&to).unwrap(), to_id).unwrap();
+        }
+    }
+
+    db.set_source_root(source_root_id, Arc::new(SourceRoot::new_local(file_set)));
+    db.set_crate_graph(Arc::new(crate_graph));
+
+    (file_position, files)
+}
+
+struct FileMeta {
+    path: String,
+    krate: Option<String>,
+    deps: Vec<String>,
+    cfg: CfgOptions,
+    edition: Edition,
+    env: Env,
+}
+
+impl From<Fixture> for FileMeta {
+    fn from(f: Fixture) -> FileMeta {
+        let mut cfg = CfgOptions::default();
+        f.cfg_atoms.iter().for_each(|it| cfg.insert_atom(it.into()));
+        f.cfg_key_values.iter().for_each(|(k, v)| cfg.insert_key_value(k.into(), v.into()));
+
+        FileMeta {
+            path: f.path,
+            krate: f.krate,
+            deps: f.deps,
+            cfg,
+            edition: f
+                .edition
+                .as_ref()
+                .map_or(Edition::Edition2018, |v| Edition::from_str(&v).unwrap()),
+            env: f.env.into_iter().collect(),
+        }
+    }
+}