Remove language-server configuration in integration tests

This change removes language server configuration from the default
languages.toml config for integration tests. No integration-tests
currently depend on the availability of a language server but if any
future test needs to, it may provide a language server configuration
by passing an override into the `test_syntax_conf` helper.

Language-servers in integration tests cause false-positive failures
when running integration tests in GitHub Actions CI. The Windows
runner appears to have `clangd` installed and all OS runners have
the `R` binary installed but not the `R` language server package.
If a test file created by `tempfile::NamedTempFile` happens to have a
file extension of `r`, the test will most likely fail because the
R language server will fail to start and will become a broken pipe,
meaning that it will fail to shutdown within the timeout, causing a
false-positive failure. This happens surprisingly often in practice.

Language servers (especially rust-analyzer) also emit unnecessary
log output when initializing, which this change silences.

helix-term/tests/test/helpers.rs

@@ -143,9 +143,27 @@ pub async fn test_key_sequence_with_input_text<T: Into<TestCase>>(
 
 /// Generates language configs that merge in overrides, like a user language
 /// config. The argument string must be a raw TOML document.
+///
+/// By default, language server configuration is dropped from the languages.toml
+/// document. If a language-server is necessary for a test, it must be explicitly
+/// added in `overrides`.
 pub fn test_syntax_conf(overrides: Option<String>) -> helix_core::syntax::Configuration {
     let mut lang = helix_loader::config::default_lang_config();
 
+    for lang_config in lang
+        .as_table_mut()
+        .expect("Expected languages.toml to be a table")
+        .get_mut("language")
+        .expect("Expected languages.toml to have \"language\" keys")
+        .as_array_mut()
+        .expect("Expected an array of language configurations")
+    {
+        lang_config
+            .as_table_mut()
+            .expect("Expected language config to be a TOML table")
+            .remove("language-server");
+    }
+
     if let Some(overrides) = overrides {
         let override_toml = toml::from_str(&overrides).unwrap();
         lang = helix_loader::merge_toml_values(lang, override_toml, 3);
@@ -236,14 +254,24 @@ pub fn new_readonly_tempfile() -> anyhow::Result<NamedTempFile> {
     Ok(file)
 }
 
-#[derive(Default)]
 pub struct AppBuilder {
     args: Args,
     config: Config,
     syn_conf: helix_core::syntax::Configuration,
     input: Option<(String, Selection)>,
 }
 
+impl Default for AppBuilder {
+    fn default() -> Self {
+        Self {
+            args: Args::default(),
+            config: Config::default(),
+            syn_conf: test_syntax_conf(None),
+            input: None,
+        }
+    }
+}
+
 impl AppBuilder {
     pub fn new() -> Self {
         AppBuilder::default()