Implemented more robust LSP diagnostics and better parsing logic

test/lsp_fuzz_test.go

@@ -0,0 +1,101 @@
+package integration
+
+import (
+	"math/rand"
+	"testing"
+	"time"
+
+	"github.com/marte-community/marte-dev-tools/internal/lsp"
+)
+
+func TestIncrementalFuzz(t *testing.T) {
+	// Initialize
+	lsp.Documents = make(map[string]string)
+	uri := "file://fuzz.marte"
+	currentText := ""
+	lsp.Documents[uri] = currentText
+
+	rand.Seed(time.Now().UnixNano())
+
+	// Apply 1000 random edits
+	for i := 0; i < 1000; i++ {
+		// Randomly choose Insert or Delete
+		isInsert := rand.Intn(2) == 0
+		
+		change := lsp.TextDocumentContentChangeEvent{}
+		
+		// Use simple ascii string
+		length := len(currentText)
+        
+		if isInsert || length == 0 {
+			// Insert
+			pos := 0
+			if length > 0 {
+				pos = rand.Intn(length + 1)
+			}
+		
+			insertStr := "X"
+			if rand.Intn(5) == 0 { insertStr = "\n" }
+			if rand.Intn(10) == 0 { insertStr = "longstring" }
+		
+            // Calculate Line/Char for pos
+            line, char := offsetToLineChar(currentText, pos)
+            
+			change.Range = &lsp.Range{
+				Start: lsp.Position{Line: line, Character: char},
+				End:   lsp.Position{Line: line, Character: char},
+			}
+			change.Text = insertStr
+			
+			// Expected
+			currentText = currentText[:pos] + insertStr + currentText[pos:]
+		} else {
+			// Delete
+			start := rand.Intn(length)
+			end := start + 1 + rand.Intn(length - start) // at least 1 char
+			
+			// Range
+            l1, c1 := offsetToLineChar(currentText, start)
+            l2, c2 := offsetToLineChar(currentText, end)
+            
+			change.Range = &lsp.Range{
+				Start: lsp.Position{Line: l1, Character: c1},
+				End:   lsp.Position{Line: l2, Character: c2},
+			}
+			change.Text = ""
+			
+			currentText = currentText[:start] + currentText[end:]
+		}
+		
+		// Apply
+		lsp.HandleDidChange(lsp.DidChangeTextDocumentParams{
+			TextDocument:   lsp.VersionedTextDocumentIdentifier{URI: uri, Version: i},
+			ContentChanges: []lsp.TextDocumentContentChangeEvent{change},
+		})
+		
+		// Verify
+		if lsp.Documents[uri] != currentText {
+			t.Fatalf("Fuzz iteration %d failed.\nExpected len: %d\nGot len:      %d\nChange: %+v", i, len(currentText), len(lsp.Documents[uri]), change)
+		}
+	}
+}
+
+func offsetToLineChar(text string, offset int) (int, int) {
+    line := 0
+    char := 0
+    for i, r := range text {
+        if i == offset {
+            return line, char
+        }
+        if r == '\n' {
+            line++
+            char = 0
+        } else {
+            char++
+        }
+    }
+    if offset == len(text) {
+        return line, char
+    }
+    return -1, -1
+}