1 files changed, 57 insertions, 0 deletions
diff --git a/parser/parser_test.go b/parser/parser_test.go
index 828db24..d3e2d1d 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -259,3 +259,60 @@ func testIntegerLiteral(t *testing.T, il ast.Expression, value int64) bool {
 
 	return true
 }
+
+// Infix expression tests.
+
+func TestParsingInfixExpressions(t *testing.T) {
+	var 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 {
+		var l *lexer.Lexer = lexer.New(tt.input)
+		var p *Parser = New(l)
+
+		var program *ast.Program = p.ParseProgram()
+		checkParserErrors(t, p)
+
+
+		if len(program.Statements) != 1 {
+			t.Fatalf("program.Statements does not contain %d statements, got=%d\n", 1, len(program.Statements))
+		}
+
+		stmt, ok := program.Statements[0].(*ast.ExpressionStatement)
+
+		if !ok {
+			t.Fatalf("program.Statements[0] is not ast.ExpressionStatement, got=%T", program.Statements[0])
+		}
+
+		exp, ok := stmt.Expression.(*ast.InfixExpression)
+
+		if !ok {
+			t.Fatalf("exp is not ast.InfixExpression. got=%T", stmt.Expression)
+		}
+
+		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)
+		}
+
+		if !testIntegerLiteral(t, exp.Right, tt.rightValue) {
+			return
+		}
+	}
+}