Add MockAnalysis to make testing easier

crates/ra_analysis/src/mock_analysis.rs

@@ -2,11 +2,19 @@
 use std::sync::Arc;
 
 use relative_path::{RelativePath, RelativePathBuf};
+use ra_syntax::TextUnit;
+use test_utils::{extract_offset, parse_fixture, CURSOR_MARKER};
 
 use crate::{
     AnalysisChange, Analysis, AnalysisHost, FileId, FileResolver,
 };
 
+#[derive(Debug)]
+pub struct FilePosition {
+    pub file_id: FileId,
+    pub offset: TextUnit,
+}
+
 /// Mock analysis is used in test to bootstrap an AnalysisHost/Analysis
 /// from a set of in-memory files.
 #[derive(Debug, Default)]
@@ -18,11 +26,57 @@ impl MockAnalysis {
     pub fn new() -> MockAnalysis {
         MockAnalysis::default()
     }
-    pub fn with_files(files: &[(&str, &str)]) -> MockAnalysis {
-        let files = files.iter()
-            .map(|it| (it.0.to_string(), it.1.to_string()))
-            .collect();
-        MockAnalysis { files }
+    /// Creates `MockAnalysis` using a fixture data in the following format:
+    ///
+    /// ```notrust
+    /// //- /main.rs
+    /// mod foo;
+    /// fn main() {}
+    ///
+    /// //- /foo.rs
+    /// struct Baz;
+    /// ```
+    pub fn with_files(fixture: &str) -> MockAnalysis {
+        let mut res = MockAnalysis::new();
+        for entry in parse_fixture(fixture) {
+            res.add_file(&entry.meta, &entry.text);
+        }
+        res
+    }
+
+    /// Same as `with_files`, but requires that a single file contains a `<|>` marker,
+    /// whose position is also returned.
+    pub fn with_files_and_position(fixture: &str) -> (MockAnalysis, FilePosition) {
+        let mut position = None;
+        let mut res = MockAnalysis::new();
+        for entry in parse_fixture(fixture) {
+            if entry.text.contains(CURSOR_MARKER) {
+                assert!(position.is_none(), "only one marker (<|>) per fixture is allowed");
+                position = Some(res.add_file_with_position(&entry.meta, &entry.text));
+            } else {
+                res.add_file(&entry.meta, &entry.text);
+            }
+        }
+        let position = position.expect("expected a marker (<|>)");
+        (res, position)
+    }
+
+    pub fn add_file(&mut self, path: &str, text: &str) -> FileId {
+        let file_id = FileId((self.files.len() + 1) as u32);
+        self.files.push((path.to_string(), text.to_string()));
+        file_id
+    }
+    pub fn add_file_with_position(&mut self, path: &str, text: &str) -> FilePosition {
+        let (offset, text) = extract_offset(text);
+        let file_id = FileId((self.files.len() + 1) as u32);
+        self.files.push((path.to_string(), text.to_string()));
+        FilePosition { file_id, offset }
+    }
+    pub fn id_of(&self, path: &str) -> FileId {
+        let (idx, _) = self.files.iter().enumerate()
+            .find(|(_, (p, _text))| path == p)
+            .expect("no file in this mock");
+        FileId(idx as u32 + 1)
     }
     pub fn analysis_host(self) -> AnalysisHost {
         let mut host = AnalysisHost::new();
@@ -44,6 +98,26 @@ impl MockAnalysis {
     }
 }
 
+/// Creates analysis from a multi-file fixture, returns positions marked with <|>.
+pub fn analysis_and_position(fixture: &str) -> (Analysis, FilePosition) {
+    let (mock, position) = MockAnalysis::with_files_and_position(fixture);
+    (mock.analysis(), position)
+}
+
+/// Creates analysis for a single file.
+pub fn single_file(code: &str) -> (Analysis, FileId) {
+    let mut mock = MockAnalysis::new();
+    let file_id = mock.add_file("/main.rs", code);
+    (mock.analysis(), file_id)
+}
+
+/// Creates analysis for a single file, returns position marked with <|>.
+pub fn single_file_with_position(code: &str) -> (Analysis, FilePosition) {
+    let mut mock = MockAnalysis::new();
+    let pos = mock.add_file_with_position("/main.rs", code);
+    (mock.analysis(), pos)
+}
+
 #[derive(Debug)]
 struct FileMap(Vec<(FileId, RelativePathBuf)>);