private static final String GROUP_ID = "test";

    // fields -----------------------------------------------------------------

    protected Artifact a1;

    protected Artifact a2;

    protected Artifact b1;

    private final String roleHint;

    @Inject
    private ArtifactFactory artifactFactory;

    private ConflictResolver conflictResolver;

    @Inject

    String[] a2 = generator.generateFresh(String[].class);
    assertFalse(a1[0].equals(a2[0]));
  }

  public void testPrimitiveArray() {
    FreshValueGenerator generator = new FreshValueGenerator();
    int[] a1 = generator.generateFresh(int[].class);
    int[] a2 = generator.generateFresh(int[].class);
    assertTrue(a1[0] != a2[0]);
  }

  public void testRange() {

@Deprecated
public class GraphTest {

    @Test
    void testCycle() throws Graph.CycleDetectedException {
        Graph graph = new Graph();
        graph.addEdge("a1", "a2");
        assertThrows(Graph.CycleDetectedException.class, () -> graph.addEdge("a2", "a1"));
    }

    @Test
    public void testPerf() throws IOException {
        List<String[]> data = new ArrayList<>();
        String k = null;

                return model;
            }
        }
    }

    private boolean withinSameGav(Artifact a1, Artifact a2) {
        return Objects.equals(a1.getGroupId(), a2.getGroupId())
                && Objects.equals(a1.getArtifactId(), a2.getArtifactId())
                && Objects.equals(a1.getVersion(), a2.getVersion());
    }

    private Properties toProperties(Map<String, String> dominant, Map<String, String> recessive) {

    //
    // 1. Subscribers to events posted on different threads can be interleaved with each other
    //    freely. (A event on one thread, B event on another could yield any of
    //    [a1, a2, a3, b1, b2], [a1, b2, a2, a3, b2], [a1, b2, b3, a2, a3], etc.)
    // 2. It's possible for subscribers to actually be dispatched to in a different order than they
    //    were added to the queue. It's easily possible for one thread to take the head of the

         *   v1<
         *       v3-v4
         *
         */
        v1 = graph.addVertex(new ArtifactMetadata("g", "a1", "1.0"));
        graph.setEntry(v1);
        v2 = graph.addVertex(new ArtifactMetadata("g", "a2", "1.0"));
        v3 = graph.addVertex(new ArtifactMetadata("g", "a3", "1.0"));
        v4 = graph.addVertex(new ArtifactMetadata("g", "a4", "1.0"));

        // v1-->v2

        // Build up an artifactMap
        project.addArtifact(new Artifact("g0", "a0", "v0", "e0", "c0"));
        project.addArtifact(new Artifact("g1", "a1", "v1", "e1", "c1"));
        project.addArtifact(new Artifact("g2", "a2", "v2", "e2", "c2"));
    }

    /**
     * <p>testValueExtraction.</p>
     *
     * @throws Exception if any.
     */
    @Test
    void testValueExtraction() throws Exception {

// a global variable access while dynamic linking, we get an error.
// See issue 43661.

TEXT ·a1(SB), 0, $0-0
	CMPL runtime·writeBarrier(SB), $0
	MOVL $0, R15
	RET
TEXT ·a2(SB), 0, $0-0
	CMPL runtime·writeBarrier(SB), $0
	MOVQ $0, R15
	RET
TEXT ·a3(SB), 0, $0-0
	CMPL runtime·writeBarrier(SB), $0
	XORL R15, R15
	RET
TEXT ·a4(SB), 0, $0-0
	CMPL runtime·writeBarrier(SB), $0

         *
         */
        graph = new MetadataGraph(4, 3);
        v1 = graph.addVertex(new ArtifactMetadata("g", "a1", "1.0"));
        graph.setEntry(v1);
        v2 = graph.addVertex(new ArtifactMetadata("g", "a2", "1.0"));
        v3 = graph.addVertex(new ArtifactMetadata("g", "a3", "1.0"));
        v4 = graph.addVertex(new ArtifactMetadata("g", "a4", "1.0"));

        // v1-->v2

```

</div>

////

当学习[虚拟环境](virtual-environments.md)时，这些信息将会很有用。

## 结论

通过这个教程，你应该对**环境变量**是什么以及如何在 Python 中使用它们有了基本的了解。

你也可以在<a href="https://zh.wikipedia.org/wiki/%E7%8E%AF%E5%A2%83%E5%8F%98%E9%87%8F" class="external-link" target="_blank">环境变量 - 维基百科</a> (<a href="https://en.wikipedia.org/wiki/Environment_variable" class="external-link" target="_blank">Wikipedia for Environment Variable</a>) 中了解更多关于它们的信息。