Testing: expose a future from the Simulation.start method to let you find out when the simulation has finished (if it finishes at all).

Add a simple test that just forces the IRS simulation through to completion (no real checks on the output).

src/test/kotlin/core/testing/IRSSimulationTest.kt

@@ -0,0 +1,23 @@
+package core.testing
+
+import com.google.common.base.Throwables
+import core.utilities.BriefLogFormatter
+import org.junit.Test
+
+/**
+ * This test doesn't check anything except that the simulation finishes and there are no exceptions at any point.
+ * The details of the IRS contract are verified in other unit tests.
+ */
+class IRSSimulationTest {
+    @Test fun `runs to completion`() {
+        BriefLogFormatter.initVerbose("messaging")
+        val sim = IRSSimulation(false, null)
+        val future = sim.start()
+        while (!future.isDone) sim.iterate()
+        try {
+            future.get()
+        } catch(e: Throwable) {
+            throw Throwables.getRootCause(e)
+        }
+    }
+}