feat(mssql): add MSSQL writer for generating DDL from database schema

- Implement MSSQL writer to generate SQL scripts for creating schemas, tables, and constraints.
- Support for identity columns, indexes, and extended properties.
- Add tests for column definitions, table creation, primary keys, foreign keys, and comments.
- Include testing guide and sample schema for integration tests.

pkg/readers/mssql/reader_test.go

@@ -0,0 +1,86 @@
+package mssql
+
+import (
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/mssql"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+	"github.com/stretchr/testify/assert"
+)
+
+// TestMapDataType tests MSSQL type mapping to canonical types
+func TestMapDataType(t *testing.T) {
+	reader := NewReader(&readers.ReaderOptions{})
+
+	tests := []struct {
+		name         string
+		mssqlType    string
+		expectedType string
+	}{
+		{"INT to int", "INT", "int"},
+		{"BIGINT to int64", "BIGINT", "int64"},
+		{"BIT to bool", "BIT", "bool"},
+		{"NVARCHAR to string", "NVARCHAR(255)", "string"},
+		{"DATETIME2 to timestamp", "DATETIME2", "timestamp"},
+		{"DATETIMEOFFSET to timestamptz", "DATETIMEOFFSET", "timestamptz"},
+		{"UNIQUEIDENTIFIER to uuid", "UNIQUEIDENTIFIER", "uuid"},
+		{"FLOAT to float64", "FLOAT", "float64"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := reader.mapDataType(tt.mssqlType)
+			assert.Equal(t, tt.expectedType, result)
+		})
+	}
+}
+
+// TestConvertCanonicalToMSSQL tests canonical to MSSQL type conversion
+func TestConvertCanonicalToMSSQL(t *testing.T) {
+	tests := []struct {
+		name           string
+		canonicalType  string
+		expectedMSSQL  string
+	}{
+		{"int to INT", "int", "INT"},
+		{"int64 to BIGINT", "int64", "BIGINT"},
+		{"bool to BIT", "bool", "BIT"},
+		{"string to NVARCHAR(255)", "string", "NVARCHAR(255)"},
+		{"text to NVARCHAR(MAX)", "text", "NVARCHAR(MAX)"},
+		{"timestamp to DATETIME2", "timestamp", "DATETIME2"},
+		{"timestamptz to DATETIMEOFFSET", "timestamptz", "DATETIMEOFFSET"},
+		{"uuid to UNIQUEIDENTIFIER", "uuid", "UNIQUEIDENTIFIER"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := mssql.ConvertCanonicalToMSSQL(tt.canonicalType)
+			assert.Equal(t, tt.expectedMSSQL, result)
+		})
+	}
+}
+
+// TestConvertMSSQLToCanonical tests MSSQL to canonical type conversion
+func TestConvertMSSQLToCanonical(t *testing.T) {
+	tests := []struct {
+		name           string
+		mssqlType      string
+		expectedType   string
+	}{
+		{"INT to int", "INT", "int"},
+		{"BIGINT to int64", "BIGINT", "int64"},
+		{"BIT to bool", "BIT", "bool"},
+		{"NVARCHAR with params", "NVARCHAR(255)", "string"},
+		{"DATETIME2 to timestamp", "DATETIME2", "timestamp"},
+		{"DATETIMEOFFSET to timestamptz", "DATETIMEOFFSET", "timestamptz"},
+		{"UNIQUEIDENTIFIER to uuid", "UNIQUEIDENTIFIER", "uuid"},
+		{"VARBINARY to bytea", "VARBINARY(MAX)", "bytea"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := mssql.ConvertMSSQLToCanonical(tt.mssqlType)
+			assert.Equal(t, tt.expectedType, result)
+		})
+	}
+}