More tests on AST

internal/parser/ast.go

@@ -45,6 +45,8 @@ type Subnode struct {
 	Definitions []Definition
 }
 
+func (s *Subnode) Pos() Position { return s.Position }
+
 type Value interface {
 	Node
 	isValue()
@@ -115,7 +117,11 @@ type Comment struct {
 	Doc      bool // true if starts with //#
 }
 
+func (c *Comment) Pos() Position { return c.Position }
+
 type Pragma struct {
 	Position Position
 	Text     string
 }
+
+func (p *Pragma) Pos() Position { return p.Position }

test/ast_test.go

@@ -84,11 +84,29 @@ func TestASTCoverage(t *testing.T) {
 
 	// Package
 	pkg := &parser.Package{Position: pos}
-	// Package implements Node?
-	// ast.go: func (p *Package) Pos() Position { return p.Position }
-	// Yes.
 	n = pkg
 	if n.Pos() != pos {
 		t.Error("Package.Pos failed")
 	}
+
+	// Subnode
+	sn := &parser.Subnode{Position: pos}
+	n = sn
+	if n.Pos() != pos {
+		t.Error("Subnode.Pos failed")
+	}
+
+	// Comment
+	cmt := &parser.Comment{Position: pos}
+	n = cmt
+	if n.Pos() != pos {
+		t.Error("Comment.Pos failed")
+	}
+
+	// Pragma
+	prg := &parser.Pragma{Position: pos}
+	n = prg
+	if n.Pos() != pos {
+		t.Error("Pragma.Pos failed")
+	}
 }