feat(writer): enhance type conversion for PostgreSQL compatibility and add tests

pkg/writers/pgsql/writer_test.go

@@ -241,3 +241,67 @@ func TestIsIntegerType(t *testing.T) {
 		}
 	}
 }
+
+func TestTypeConversion(t *testing.T) {
+	// Test that invalid Go types are converted to valid PostgreSQL types
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create a test table with Go types instead of SQL types
+	table := models.InitTable("test_types", "public")
+
+	// Add columns with Go types (invalid for PostgreSQL)
+	stringCol := models.InitColumn("name", "test_types", "public")
+	stringCol.Type = "string" // Should be converted to "text"
+	table.Columns["name"] = stringCol
+
+	int64Col := models.InitColumn("big_id", "test_types", "public")
+	int64Col.Type = "int64" // Should be converted to "bigint"
+	table.Columns["big_id"] = int64Col
+
+	int16Col := models.InitColumn("small_id", "test_types", "public")
+	int16Col.Type = "int16" // Should be converted to "smallint"
+	table.Columns["small_id"] = int16Col
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer with output to buffer
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	// Write the database
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Print output for debugging
+	t.Logf("Generated SQL:\n%s", output)
+
+	// Verify that Go types were converted to PostgreSQL types
+	if strings.Contains(output, "string") {
+		t.Errorf("Output contains 'string' type - should be converted to 'text'\nFull output:\n%s", output)
+	}
+	if strings.Contains(output, "int64") {
+		t.Errorf("Output contains 'int64' type - should be converted to 'bigint'\nFull output:\n%s", output)
+	}
+	if strings.Contains(output, "int16") {
+		t.Errorf("Output contains 'int16' type - should be converted to 'smallint'\nFull output:\n%s", output)
+	}
+
+	// Verify correct PostgreSQL types are present
+	if !strings.Contains(output, "text") {
+		t.Errorf("Output missing 'text' type (converted from 'string')\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "bigint") {
+		t.Errorf("Output missing 'bigint' type (converted from 'int64')\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "smallint") {
+		t.Errorf("Output missing 'smallint' type (converted from 'int16')\nFull output:\n%s", output)
+	}
+}