1 files changed, 91 insertions, 0 deletions
diff --git a/parser/parser_test.go b/parser/parser_test.go
new file mode 100644
index 0000000..8f78c8b
--- /dev/null
+++ b/parser/parser_test.go
@@ -0,0 +1,91 @@
+package parser
+
+import (
+	"testing"
+	"mana/ast"
+	"mana/lexer"
+)
+
+func TestLetStatements(t *testing.T) {
+	const input string = `
+		let x = 5;
+		let y = 10;
+		let foobar = 838383;
+	`
+
+	var l *lexer.Lexer = lexer.New(input)
+	var p *Parser = New(l)
+
+	var program *ast.Program = p.ParseProgram()
+	checkParserErrors(t, p)
+
+	if program == nil {
+		t.Fatalf("ParseProgram() returned nil")
+	}
+
+	if len(program.Statements) != 3 {
+		t.Fatalf("program.Statements does not contain 3 statements. got=%d", len(program.Statements))
+	}
+
+	var tests = []struct {
+		expectedIdentifier string
+	}{
+		{"x"},
+		{"y"},
+		{"foobar"},
+	}
+
+	for i, tt := range tests {
+		var stmt ast.Statement = program.Statements[i]
+
+		if !testLetStatement(t, stmt, tt.expectedIdentifier) {
+			return
+		}
+	}
+}
+
+func checkParserErrors(t *testing.T, p *Parser) {
+	var errors []string = p.Errors()
+
+	if len(errors) == 0 {
+		return
+	}
+
+	t.Errorf("parser has %d errors", len(errors))
+
+	for _, msg := range errors {
+		t.Errorf("parser error: %q", msg)
+	}
+
+	t.FailNow()
+}
+
+func testLetStatement(t *testing.T, s ast.Statement, name string) bool {
+	if s.TokenLiteral() != "let" {
+		t.Errorf("s.TokenLiteral not 'let'. got=%q", s.TokenLiteral())
+
+		return false
+	}
+
+	var letStmt, ok = s.(*ast.LetStatement)
+
+	if !ok {
+		t.Errorf("s not *ast.LetStatement. got=%T", s)
+
+		return false
+	}
+
+	if letStmt.Name.Value != name {
+		t.Errorf("letStmt.Name.Value not '%s'. got=%s", name, letStmt.Name.Value)
+
+		return false
+	}
+
+	if letStmt.Name.TokenLiteral() != name {
+		t.Errorf("letStmt.Name.TokenLiteral() not '%s'. got=%s", name, letStmt.Name.TokenLiteral())
+
+		return false
+	}
+
+	return true
+}