Fix target directory resolution

This is a hack which doesn't work for doc-tests but the previous
approach didn't work for workspaces. Given that the expectation is that
these files will most likely be used in integration tests I'm going with
this approach.

See: rust-lang/cargo#2841

Author: robyoung

rust/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "dicom-test-files"
-version = "0.1.1"
+version = "0.1.2"
 authors = ["Rob Young <[email protected]>"]
 edition = "2018"
 description = "A collection of DICOM files for testing DICOM parsers." 

rust/src/lib.rs

@@ -3,7 +3,7 @@
 //! To avoid users having to download all the files they are downloaded as they
 //! are needed and cached in the `/target` directory.
 //!
-//! ```rust
+//! ```no_run
 //! use dicom_test_files;
 //!
 //! dicom_test_files::path("pydicom/liver.dcm").unwrap();
@@ -53,7 +53,13 @@ pub fn path(name: &str) -> Result<PathBuf, Error> {
 }
 
 pub(crate) fn get_data_path() -> PathBuf {
-    PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap()).join("target").join("dicom_test_files")
+    let mut target_dir = PathBuf::from(env::current_exe().expect("exe path").parent().expect("exe parent"));
+    while target_dir.file_name() != Some(std::ffi::OsStr::new("target")) {
+        if !target_dir.pop() {
+            panic!("Cannot find target directory");
+        }
+    }
+    target_dir.join("dicom_test_files")
 }
 
 const GITHUB_BASE_URL: &str = "https://raw.githubusercontent.com/robyoung/dicom-test-files/master/data/";