diff --git a/test/logger_test.go b/test/logger_test.go
new file mode 100644
index 0000000..667d2ea
--- /dev/null
+++ b/test/logger_test.go
@@ -0,0 +1,59 @@
+package integration
+
+import (
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+
+	"github.com/marte-community/marte-dev-tools/internal/logger"
+)
+
+func TestLoggerPrint(t *testing.T) {
+	if os.Getenv("TEST_LOGGER_PRINT") == "1" {
+		logger.Printf("Test Printf %d", 123)
+		logger.Println("Test Println")
+		return
+	}
+	cmd := exec.Command(os.Args[0], "-test.run=TestLoggerPrint")
+	cmd.Env = append(os.Environ(), "TEST_LOGGER_PRINT=1")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("process failed: %v", err)
+	}
+	output := string(out)
+	if !strings.Contains(output, "Test Printf 123") {
+		t.Error("Printf output missing")
+	}
+	if !strings.Contains(output, "Test Println") {
+		t.Error("Println output missing")
+	}
+}
+
+func TestLoggerFatal(t *testing.T) {
+	if os.Getenv("TEST_LOGGER_FATAL") == "1" {
+		logger.Fatal("Test Fatal")
+		return
+	}
+	cmd := exec.Command(os.Args[0], "-test.run=TestLoggerFatal")
+	cmd.Env = append(os.Environ(), "TEST_LOGGER_FATAL=1")
+	err := cmd.Run()
+	if e, ok := err.(*exec.ExitError); ok && !e.Success() {
+		return // Success (exit code non-zero)
+	}
+	t.Fatalf("process ran with err %v, want exit status 1", err)
+}
+
+func TestLoggerFatalf(t *testing.T) {
+	if os.Getenv("TEST_LOGGER_FATALF") == "1" {
+		logger.Fatalf("Test Fatalf %d", 456)
+		return
+	}
+	cmd := exec.Command(os.Args[0], "-test.run=TestLoggerFatalf")
+	cmd.Env = append(os.Environ(), "TEST_LOGGER_FATALF=1")
+	err := cmd.Run()
+	if e, ok := err.(*exec.ExitError); ok && !e.Success() {
+		return // Success
+	}
+	t.Fatalf("process ran with err %v, want exit status 1", err)
+}
diff --git a/test/lsp_coverage_test.go b/test/lsp_coverage_test.go
new file mode 100644
index 0000000..8c51204
--- /dev/null
+++ b/test/lsp_coverage_test.go
@@ -0,0 +1,110 @@
+package integration
+
+import (
+	"bytes"
+	"encoding/json"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+
+	"github.com/marte-community/marte-dev-tools/internal/lsp"
+)
+
+func TestLSPIncrementalSync(t *testing.T) {
+	lsp.Documents = make(map[string]string)
+	var buf bytes.Buffer
+	lsp.Output = &buf
+	
+	content := "Line1\nLine2\nLine3"
+	uri := "file://inc.marte"
+	lsp.Documents[uri] = content 
+
+	// Replace "Line2" (Line 1, 0-5) with "Modified"
+	change := lsp.TextDocumentContentChangeEvent{
+		Range: &lsp.Range{
+			Start: lsp.Position{Line: 1, Character: 0},
+			End:   lsp.Position{Line: 1, Character: 5},
+		},
+		Text: "Modified",
+	}
+	
+	params := lsp.DidChangeTextDocumentParams{
+		TextDocument: lsp.VersionedTextDocumentIdentifier{URI: uri, Version: 2},
+		ContentChanges: []lsp.TextDocumentContentChangeEvent{change},
+	}
+	
+lsp.HandleDidChange(params)
+	
+	expected := "Line1\nModified\nLine3"
+	if lsp.Documents[uri] != expected {
+		t.Errorf("Incremental update failed. Got:\n%q\nWant:\n%q", lsp.Documents[uri], expected)
+	}
+	
+	// Insert at end
+	change2 := lsp.TextDocumentContentChangeEvent{
+		Range: &lsp.Range{
+			Start: lsp.Position{Line: 2, Character: 5},
+			End:   lsp.Position{Line: 2, Character: 5},
+		},
+		Text: "\nLine4",
+	}
+	params2 := lsp.DidChangeTextDocumentParams{
+		TextDocument: lsp.VersionedTextDocumentIdentifier{URI: uri, Version: 3},
+		ContentChanges: []lsp.TextDocumentContentChangeEvent{change2},
+	}
+	lsp.HandleDidChange(params2)
+	
+	expected2 := "Line1\nModified\nLine3\nLine4"
+	if lsp.Documents[uri] != expected2 {
+		t.Errorf("Incremental insert failed. Got:\n%q\nWant:\n%q", lsp.Documents[uri], expected2)
+	}
+}
+
+func TestLSPLifecycle(t *testing.T) {
+	var buf bytes.Buffer
+	lsp.Output = &buf
+	
+	// Shutdown
+	msgShutdown := &lsp.JsonRpcMessage{
+		Method: "shutdown",
+		ID: 1,
+	}
+	lsp.HandleMessage(msgShutdown)
+	
+	if !strings.Contains(buf.String(), `"result":null`) {
+		t.Error("Shutdown response incorrect")
+	}
+	
+	// Exit
+	if os.Getenv("TEST_LSP_EXIT") == "1" {
+		msgExit := &lsp.JsonRpcMessage{Method: "exit"}
+		lsp.HandleMessage(msgExit)
+		return
+	}
+	cmd := exec.Command(os.Args[0], "-test.run=TestLSPLifecycle")
+	cmd.Env = append(os.Environ(), "TEST_LSP_EXIT=1")
+	err := cmd.Run()
+	if err != nil {
+		t.Errorf("Exit failed: %v", err)
+	}
+}
+
+func TestLSPMalformedParams(t *testing.T) {
+	var buf bytes.Buffer
+	lsp.Output = &buf
+
+	// Malformed Hover
+	msg := &lsp.JsonRpcMessage{
+		Method: "textDocument/hover",
+		ID: 2,
+		Params: json.RawMessage(`{invalid`),
+	}
+	lsp.HandleMessage(msg)
+	
+	output := buf.String()
+	// Should respond with nil result
+	if !strings.Contains(output, `"result":null`) {
+		t.Errorf("Expected nil result for malformed params, got: %s", output)
+	}
+}