TestSystem

TestSystem supports deterministic testing of effects involving system properties. Internally, TestSystem maintains mappings of environment variables and system properties that can be set and accessed. No actual environment variables or system properties will be accessed or set as a result of these actions.

import zio.system
import zio.test.TestSystem

for {
  _      <- TestSystem.putProperty("java.vm.name", "VM")
  result <- system.property("java.vm.name")
} yield result == Some("VM")