1 files changed, 79 insertions, 0 deletions
diff --git a/grammar/lexical/dfa/symbol_position_test.go b/grammar/lexical/dfa/symbol_position_test.go
new file mode 100644
index 0000000..c867f64
--- /dev/null
+++ b/grammar/lexical/dfa/symbol_position_test.go
@@ -0,0 +1,79 @@
+package dfa
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestNewSymbolPosition(t *testing.T) {
+	tests := []struct {
+		n       uint16
+		endMark bool
+		err     bool
+	}{
+		{
+			n:       0,
+			endMark: false,
+			err:     true,
+		},
+		{
+			n:       0,
+			endMark: true,
+			err:     true,
+		},
+		{
+			n:       symbolPositionMin - 1,
+			endMark: false,
+			err:     true,
+		},
+		{
+			n:       symbolPositionMin - 1,
+			endMark: true,
+			err:     true,
+		},
+		{
+			n:       symbolPositionMin,
+			endMark: false,
+		},
+		{
+			n:       symbolPositionMin,
+			endMark: true,
+		},
+		{
+			n:       symbolPositionMax,
+			endMark: false,
+		},
+		{
+			n:       symbolPositionMax,
+			endMark: true,
+		},
+		{
+			n:       symbolPositionMax + 1,
+			endMark: false,
+			err:     true,
+		},
+		{
+			n:       symbolPositionMax + 1,
+			endMark: true,
+			err:     true,
+		},
+	}
+	for i, tt := range tests {
+		t.Run(fmt.Sprintf("#%v n: %v, endMark: %v", i, tt.n, tt.endMark), func(t *testing.T) {
+			pos, err := newSymbolPosition(tt.n, tt.endMark)
+			if tt.err {
+				if err == nil {
+					t.Fatal("err is nil")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatal(err)
+			}
+			n, endMark := pos.describe()
+			if n != tt.n || endMark != tt.endMark {
+				t.Errorf("unexpected symbol position: want: n: %v, endMark: %v, got: n: %v, endMark: %v", tt.n, tt.endMark, n, endMark)
+			}
+		})
+	}
+}