move examples/test/*.java to ortools/<component>/java

ortools/graph/java/FlowTest.java

@@ -0,0 +1,81 @@
+// Copyright 2010-2022 Google LLC
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.ortools.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import com.google.ortools.Loader;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/** Test the Min/Max Flow solver java interface. */
+public final class FlowTest {
+  @BeforeEach
+  public void setUp() {
+    Loader.loadNativeLibraries();
+  }
+
+  @Test
+  public void testMinCostFlow() {
+    final int numSources = 4;
+    final int numTargets = 4;
+    final int[][] costs = {
+        {90, 75, 75, 80}, {35, 85, 55, 65}, {125, 95, 90, 105}, {45, 110, 95, 115}};
+    final int expectedCost = 275;
+    final MinCostFlow minCostFlow = new MinCostFlow();
+    assertNotNull(minCostFlow);
+    for (int source = 0; source < numSources; ++source) {
+      for (int target = 0; target < numTargets; ++target) {
+        minCostFlow.addArcWithCapacityAndUnitCost(
+            source, numSources + target, 1, costs[source][target]);
+      }
+    }
+
+    for (int source = 0; source < numSources; ++source) {
+      minCostFlow.setNodeSupply(source, 1);
+    }
+    for (int target = 0; target < numTargets; ++target) {
+      minCostFlow.setNodeSupply(numSources + target, -1);
+    }
+    final MinCostFlowBase.Status solveStatus = minCostFlow.solve();
+    assertEquals(solveStatus, MinCostFlow.Status.OPTIMAL);
+    final long totalFlowCost = minCostFlow.getOptimalCost();
+    assertEquals(expectedCost, totalFlowCost);
+  }
+
+  @Test
+  public void testMaxFlow() {
+    final int numNodes = 6;
+    final int numArcs = 9;
+    final int[] tails = {0, 0, 0, 0, 1, 2, 3, 3, 4};
+    final int[] heads = {1, 2, 3, 4, 3, 4, 4, 5, 5};
+    final int[] capacities = {5, 8, 2, 0, 4, 5, 6, 0, 4};
+    final int[] expectedFlows = {4, 4, 2, 0, 4, 4, 0, 6, 4};
+    final int expectedTotalFlow = 10;
+    final MaxFlow maxFlow = new MaxFlow();
+    assertNotNull(maxFlow);
+    for (int i = 0; i < numArcs; ++i) {
+      maxFlow.addArcWithCapacity(tails[i], heads[i], capacities[i]);
+    }
+    maxFlow.setArcCapacity(7, 6);
+    final MaxFlow.Status solveStatus = maxFlow.solve(/*source=*/0, /*sink=*/numNodes - 1);
+    assertEquals(solveStatus, MaxFlow.Status.OPTIMAL);
+    final long totalFlow = maxFlow.getOptimalFlow();
+    assertEquals(expectedTotalFlow, totalFlow);
+    for (int i = 0; i < numArcs; ++i) {
+      assertEquals(maxFlow.getFlow(i), expectedFlows[i]);
+    }
+  }
+}