mermaid-go/tests/lexer_test.go

package tests

import (
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"mermaid-go/pkg/lexer"
)

func TestLexer_TokenizeBasicGraph(t *testing.T) {
	input := "graph TD\nA --> B"

	l := lexer.NewLexer(input)
	tokens, err := l.Tokenize()

	require.NoError(t, err)
	require.NotEmpty(t, tokens)

	// Filter out whitespace for easier testing
	filtered := lexer.FilterTokens(tokens)

	expected := []lexer.TokenType{
		lexer.TokenGraph,
		lexer.TokenTD,
		lexer.TokenID,         // A
		lexer.TokenArrowSolid, // -->
		lexer.TokenID,         // B
		lexer.TokenEOF,
	}

	require.Len(t, filtered, len(expected))

	for i, expectedType := range expected {
		assert.Equal(t, expectedType, filtered[i].Type,
			"Token %d: expected %s, got %s", i, expectedType, filtered[i].Type)
	}
}

func TestLexer_TokenizeWithShapes(t *testing.T) {
	input := `A[Text] --> B(Round) --> C{Diamond}`

	l := lexer.NewLexer(input)
	tokens, err := l.Tokenize()

	require.NoError(t, err)

	filtered := lexer.FilterTokens(tokens)

	// Should tokenize: A [ Text ] --> B ( Round ) --> C { Diamond } EOF
	expectedTypes := []lexer.TokenType{
		lexer.TokenID,           // A
		lexer.TokenOpenBracket,  // [
		lexer.TokenID,           // Text
		lexer.TokenCloseBracket, // ]
		lexer.TokenArrowSolid,   // -->
		lexer.TokenID,           // B
		lexer.TokenOpenParen,    // (
		lexer.TokenID,           // Round
		lexer.TokenCloseParen,   // )
		lexer.TokenArrowSolid,   // -->
		lexer.TokenID,           // C
		lexer.TokenOpenBrace,    // {
		lexer.TokenID,           // Diamond
		lexer.TokenCloseBrace,   // }
		lexer.TokenEOF,
	}

	require.Len(t, filtered, len(expectedTypes))

	for i, expectedType := range expectedTypes {
		assert.Equal(t, expectedType, filtered[i].Type,
			"Token %d: expected %s, got %s (value: %q)",
			i, expectedType, filtered[i].Type, filtered[i].Value)
	}
}

func TestLexer_TokenizeArrowTypes(t *testing.T) {
	testCases := []struct {
		input    string
		expected lexer.TokenType
	}{
		{"-->", lexer.TokenArrowSolid},
		{"-.->", lexer.TokenArrowDotted},
		{"==>", lexer.TokenArrowThick},
		{"--x", lexer.TokenArrowCross},
		{"--o", lexer.TokenArrowCircle},
		{"---", lexer.TokenArrowOpen},
	}

	for _, tc := range testCases {
		t.Run(tc.input, func(t *testing.T) {
			l := lexer.NewLexer(tc.input)
			tokens, err := l.Tokenize()
			require.NoError(t, err)

			filtered := lexer.FilterTokens(tokens)
			require.Len(t, filtered, 2) // Arrow + EOF

			assert.Equal(t, tc.expected, filtered[0].Type)
			assert.Equal(t, tc.input, filtered[0].Value)
		})
	}
}

func TestLexer_TokenizeWithLabel(t *testing.T) {
	input := `A -->|Label| B`

	l := lexer.NewLexer(input)
	tokens, err := l.Tokenize()

	require.NoError(t, err)

	filtered := lexer.FilterTokens(tokens)

	expectedTypes := []lexer.TokenType{
		lexer.TokenID,         // A
		lexer.TokenArrowSolid, // -->
		lexer.TokenPipe,       // |
		lexer.TokenID,         // Label
		lexer.TokenPipe,       // |
		lexer.TokenID,         // B
		lexer.TokenEOF,
	}

	require.Len(t, filtered, len(expectedTypes))

	for i, expectedType := range expectedTypes {
		assert.Equal(t, expectedType, filtered[i].Type,
			"Token %d: expected %s, got %s (value: %q)",
			i, expectedType, filtered[i].Type, filtered[i].Value)
	}
}

func TestLexer_TokenizeComments(t *testing.T) {
	input := `graph TD
%% This is a comment
A --> B`

	l := lexer.NewLexer(input)
	tokens, err := l.Tokenize()

	require.NoError(t, err)

	// Find comment token
	var commentFound bool
	for _, token := range tokens {
		if token.Type == lexer.TokenComment {
			commentFound = true
			assert.Equal(t, "%% This is a comment", token.Value)
		}
	}

	assert.True(t, commentFound, "Comment token not found")
}