waiig15/parser/parser_infix_test.go

package parser

import (
	"testing"

	"code.osinet.fr/fgm/waiig15/ast"
	"code.osinet.fr/fgm/waiig15/lexer"
)

func TestParsingInfixExpressions(t *testing.T) {
	infixTests := []struct {
		input      string
		leftValue  int64
		operator   string
		rightValue int64
	}{
		{"5 + 5", 5, "+", 5},
		{"5 - 5", 5, "-", 5},
		{"5 * 5", 5, "*", 5},
		{"5 / 5", 5, "/", 5},
		{"5 > 5", 5, ">", 5},
		{"5 < 5", 5, "<", 5},
		{"5 == 5", 5, "==", 5},
		{"5 != 5", 5, "!=", 5},
	}

	for _, tt := range infixTests {
		l := lexer.New(tt.input)
		p := New(l)
		program := p.ParseProgram()
		checkParserErrors(t, p)

		if len(program.Statements) != 1 {
			t.Fatalf("program.Statements does not contain %d statements. got=%d",
				1, len(program.Statements))
		}

		stmt, ok := program.Statements[0].(*ast.ExpressionStatement)
		if !ok {
			t.Fatalf("program.Statements[0] is not expressionStatement. got=%T",
				program.Statements[0])
		}

		exp, ok := stmt.Expression.(*ast.InfixExpression)
		if !ok {
			t.Fatalf("exp is not infixExpression. got=%T", stmt.Expression)
		}

		// Why no error ?
		if !testIntegerLiteral(t, exp.Left, tt.leftValue) {
			return
		}

		if exp.Operator != tt.operator {
			t.Fatalf("exp.Operator is not '%s'. got=%s", tt.operator,
				exp.Operator)
		}

		// Why no error ?
		if !testIntegerLiteral(t, exp.Right, tt.rightValue) {
			return
		}
	}
}