During some minimization efforts on the previous released version 28.2-jre, I noticed a spurious file in the published version on maven central:

```
tn@proteus:~/Downloads$ unzip -l guava-28.2-jre.jar  | grep swp
    16384  2019-09-18 17:29   com/google/common/collect/.ImmutableListMultimap.java.swp
```

Looks like an transient artefact from an editor that slipped into the release. It is not present in the android variant or in older releases (I checked at least 28.1-jre).

Minor things that can not be changed anymore but maybe a trigger for improvement of future releases.

Edit: I noticed that 29.0 has been released that does not contain this spurious file.
assertThat(e).hasMessageThat().contains(ENDPOINTS_MISMATCH);
    }
  }
  @Test
  public void addEdge_selfLoop_notAllowed() {
    assume().that(graphIsMutable()).isTrue();
    assume().that(network.allowsSelfLoops()).isFalse();
    try {
      networkAsMutableNetwork.addEdge(N1, N1, E11);
      fail(ERROR_ADDED_SELF_LOOP);
    } catch (IllegalArgumentException e) {
      assertThat(e).hasMessageThat().contains(ERROR_SELF_LOOP);
    }
  }
  /**
   * This test checks an implementation dependent feature. It tests that the method {@code addEdge}
   * will silently add the missing nodes to the graph, then add the edge connecting them. We are not
   * using the proxy methods here as we want to test {@code addEdge} when the end-points are not
   * elements of the graph.
   */
  @Test
  public void addEdge_nodesNotInGraph() {
    assume().that(graphIsMutable()).isTrue();
    networkAsMutableNetwork.addNode(N1);
    assertTrue(networkAsMutableNetwork.addEdge(N1, N5, E15));
    assertTrue(networkAsMutableNetwork.addEdge(N4, N1, E41));
    assertTrue(networkAsMutableNetwork.addEdge(N2, N3, E23));
    assertThat(network.nodes()).containsExactly(N1, N5, N4, N2, N3);
    assertThat(network.edges()).containsExactly(E15, E41, E23);
    assertThat(network.edgesConnecting(N1, N5)).containsExactly(E15);