Improved test coverage

src/build/expression/Expression.go

@@ -26,15 +26,6 @@ func NewLeaf(t token.Token) *Expression {
 	return expr
 }
 
-// NewBinary creates a new binary operator expression.
-func NewBinary(left *Expression, operator token.Token, right *Expression) *Expression {
-	expr := New()
-	expr.Token = operator
-	expr.AddChild(left)
-	expr.AddChild(right)
-	return expr
-}
-
 // AddChild adds a child to the expression.
 func (expr *Expression) AddChild(child *Expression) {
 	expr.Children = append(expr.Children, child)