test: add test for toolchain path setup

src/loglib/Logger.v

@@ -15,7 +15,7 @@ pub const support_colors = term.can_show_color_on_stderr() && term.can_show_colo
 
 @[heap]
 pub struct Logger {
-mut:
+pub mut:
 	disabled   bool
 	color_mode ColorMode
 

src/server/protocol/Client.v

@@ -25,6 +25,11 @@ pub fn (mut c Client) progress(params lsp.ProgressParams) {
 
 // log_message sends a window/logMessage notification to the client
 pub fn (mut c Client) log_message(message string, typ lsp.MessageType) {
+	$if test {
+		if c == unsafe { nil } {
+			return
+		}
+	}
 	c.wr.write_notify('window/logMessage', lsp.LogMessageParams{
 		@type: typ
 		message: message

src/server/setup_test.v

@@ -0,0 +1,73 @@
+module server
+
+import os
+import lsp
+import loglib as _ // import to use __global `logger`
+
+const default_vexe = @VEXE
+const default_vroot = os.dir(default_vexe)
+const default_vlib_root = os.join_path(default_vroot, 'vlib')
+const default_vmodules_root = os.vmodules_dir()
+
+fn test_setup_default_vpaths() {
+	mut ls := LanguageServer{}
+	ls.setup()
+	assert ls.paths.vexe == server.default_vexe
+	assert ls.paths.vroot == server.default_vroot
+	assert ls.paths.vlib_root == server.default_vlib_root
+	assert ls.paths.vmodules_root == server.default_vmodules_root
+}
+
+fn test_setup_custom_vpaths() {
+	custom_root := os.join_path(os.vtmp_dir(), 'v-analyzer-setup-test')
+	custom_root_uri := lsp.document_uri_from_path(custom_root)
+	cfg_dir_path := os.join_path(custom_root, '.v-analyzer')
+	cfg_path := os.join_path(cfg_dir_path, 'config.toml')
+	os.mkdir_all(cfg_dir_path)!
+	defer {
+		os.rmdir_all(cfg_dir_path) or {}
+	}
+
+	// Test custom_vroot with missing toolchain ==================================
+	// Use single quotes for literal strings so that paths keep working on Windows.
+	mut cfg_toml := "custom_vroot = '${custom_root}'"
+	os.write_file(cfg_path, cfg_toml)!
+
+	// Set output(io.Writer) for global loglib logger.
+	log_file_path := os.join_path(custom_root, 'log')
+	os.write_file(log_file_path, '')!
+	mut log_file := os.open_append(os.join_path(custom_root, 'log'))!
+	logger.out = log_file
+
+	// Run setup
+	mut ls := LanguageServer{}
+	ls.root_uri = custom_root_uri
+	ls.setup()
+
+	log_file.close()
+	mut log_out := os.read_file(log_file_path)!
+	println('Testlog custom_vroot missing toolchain:')
+	println(log_out.trim_space())
+	assert log_out.contains('Find custom VROOT path')
+	assert log_out.contains('Using "${custom_root}" as toolchain')
+	assert log_out.contains('Failed to find standard library path')
+
+	// Test custom_vroot with existing toolchain =================================
+	cfg_toml = "custom_vroot = '${server.default_vroot}'"
+	os.write_file(cfg_path, cfg_toml)!
+	os.write_file(log_file_path, '')!
+	log_file = os.open_append(os.join_path(custom_root, 'log'))!
+	logger.out = log_file
+
+	ls = LanguageServer{}
+	ls.root_uri = custom_root_uri
+	ls.setup()
+
+	log_file.close()
+	log_out = os.read_file(log_file_path)!
+	println('Testlog custom_vroot existing toolchain:')
+	println(log_out.trim_space())
+	assert log_out.contains('Find custom VROOT path')
+	assert log_out.contains('Using "${server.default_vroot}" as toolchain')
+	assert !log_out.contains('Failed to find standard library path')
+}