Test --web-bundle with refactored config.rs

`config.rs` is refactored such that `test-bundle://` is interpreted as
the valid web-bundle for offline testing.

Author: bryango

src/config.rs

@@ -44,6 +44,25 @@ pub fn is_config_test_mode_activated() -> bool {
     CONFIG_TEST_MODE_ACTIVATED.load(Ordering::SeqCst)
 }
 
+pub fn is_test_bundle_wanted(web_bundle: Option<String>) -> bool {
+    if !is_config_test_mode_activated() {
+        return false;
+    }
+    match web_bundle {
+        None => true,
+        Some(x) if x.contains("test-bundle://") => true,
+        _ => false,
+    }
+}
+
+pub fn maybe_return_test_bundle(web_bundle: Option<String>) -> Result<Box<dyn Bundle>> {
+    if is_test_bundle_wanted(web_bundle) {
+        Ok(Box::<crate::test_util::TestBundle>::default())
+    } else {
+        Err(ErrorKind::Msg("not asking for the default test bundle".to_owned()).into())
+    }
+}
+
 #[cfg_attr(feature = "serde", derive(Deserialize, Serialize))]
 pub struct PersistentConfig {
     default_bundles: Vec<BundleInfo>,
@@ -122,6 +141,10 @@ impl PersistentConfig {
         custom_cache_root: Option<&Path>,
         status: &mut dyn StatusBackend,
     ) -> Result<Box<dyn Bundle>> {
+        if let Ok(test_bundle) = maybe_return_test_bundle(Some(url.to_owned())) {
+            return Ok(test_bundle);
+        }
+
         let mut cache = if let Some(root) = custom_cache_root {
             Cache::get_for_custom_directory(root)
         } else {
@@ -156,9 +179,8 @@ impl PersistentConfig {
     ) -> Result<Box<dyn Bundle>> {
         use std::io;
 
-        if CONFIG_TEST_MODE_ACTIVATED.load(Ordering::SeqCst) {
-            let bundle = crate::test_util::TestBundle::default();
-            return Ok(Box::new(bundle));
+        if let Ok(test_bundle) = maybe_return_test_bundle(None) {
+            return Ok(test_bundle);
         }
 
         if self.default_bundles.len() != 1 {
@@ -183,7 +205,7 @@ impl PersistentConfig {
     }
 
     pub fn format_cache_path(&self) -> Result<PathBuf> {
-        if CONFIG_TEST_MODE_ACTIVATED.load(Ordering::SeqCst) {
+        if is_config_test_mode_activated() {
             Ok(crate::test_util::test_path(&[]))
         } else {
             Ok(app_dirs::ensure_user_cache_dir("formats")?)

tests/executable.rs

@@ -636,6 +636,37 @@ fn stdin_content() {
     success_or_panic(&output);
 }
 
+#[test]
+fn web_bundle_flag() {
+    let filename = "subdirectory/content/1.tex";
+    let fmt_arg: &str = &get_plain_format_arg();
+    let tempdir = setup_and_copy_files(&[filename]);
+    let temppath = tempdir.path().to_owned();
+
+    let arg_bad_bundle = ["--web-bundle", "bad-bundle"];
+    let arg_good_bundle = ["--web-bundle", "test-bundle://"];
+
+    // test with a bad bundle
+    let output = run_tectonic(
+        &temppath,
+        &[&arg_bad_bundle[..], &[fmt_arg, filename]].concat(),
+    );
+    error_or_panic(&output);
+
+    // test with a good bundle
+    let valid_args: Vec<Vec<&str>> = vec![
+        // different positions
+        [&arg_good_bundle[..], &[fmt_arg, filename]].concat(),
+        [&[fmt_arg], &arg_good_bundle[..], &[filename]].concat(),
+        [&[fmt_arg], &[filename], &arg_good_bundle[..]].concat(),
+    ];
+
+    for args in valid_args {
+        let output = run_tectonic(&temppath, &args);
+        success_or_panic(&output);
+    }
+}
+
 #[cfg(feature = "serialization")]
 #[test]
 fn v2_build_basic() {