test: add tests for solver

package.json

@@ -5,9 +5,12 @@
 	},
 	"dependencies": {
 		"@eslint/js": "^9.29.0",
+		"@jest/globals": "^30.0.3",
+		"@swc/jest": "^0.2.38",
 		"@types/node": "^24.0.4",
 		"eslint": "^9.29.0",
 		"globals": "^16.2.0",
+		"jest": "^30.0.3",
 		"prettier": "^3.6.0",
 		"turbo": "^2.5.4",
 		"typescript": "^5.8.3",