$ python main.py

// Now it can read the environment variable

Hello Wade Wilson from Python
```

</div>

////

As environment variables can be set outside of the code, but can be read by the code, and don't have to be stored (committed to `git`) with the rest of the files, it's common to use them for configurations or **settings**.

        sessionIdField.setAccessible(true);

        // Initially sessionId should be null
        String initialSessionId = (String) sessionIdField.get(authenticator);
        assertNull(initialSessionId, "SessionId should initially be null");
    }

    @Test
    @DisplayName("Test get password as char array")
    void testGetPasswordAsCharArray() {

    if (x <= 0) {
      throw new IllegalArgumentException(role + " (" + x + ") must be > 0");
    }
    return x;
  }

  @CanIgnoreReturnValue
  static long checkPositive(String role, long x) {
    if (x <= 0) {
      throw new IllegalArgumentException(role + " (" + x + ") must be > 0");
    }
    return x;
  }

  @CanIgnoreReturnValue

     * Creates a {@link org.apache.maven.api.Project} from a POM file.
     *
     * @param session the {@link Session}, must not be {@code null}
     * @param path the {@link Path}, must not be {@code null}
     * @throws ProjectBuilderException if the project cannot be created
     * @throws IllegalArgumentException if an argument is {@code null} or invalid
     * @see #build(ProjectBuilderRequest)
     */
    @Nonnull

    /**
     * Determines the address of a host given it's host name. The name can be a NetBIOS name like
     * "freto" or an IP address like "192.168.1.15". It cannot be a DNS name;
     * the analygous {@link jcifs.netbios.UniAddress} or {@link java.net.InetAddress}
     * <code>getByName</code> methods can be used for that.
     *
     * @param host
     *            hostname to resolve

        assertNotNull("Package should not be null", pkg);
        assertEquals("Should be in correct package", "org.codelibs.fess.tomcat.webresources", pkg.getName());
    }

    public void test_isPublicClass() {
        assertTrue("FessWebResourceRoot should be public", java.lang.reflect.Modifier.isPublic(FessWebResourceRoot.class.getModifiers()));
        assertFalse("FessWebResourceRoot should not be abstract",

   *
   * <p>All of the fields in this class are encoded in various portions of the IPv6 address as part
   * of the protocol. More protocols details can be found at: <a target="_parent"
   * href="http://en.wikipedia.org/wiki/Teredo_tunneling">http://en.wikipedia.
   * org/wiki/Teredo_tunneling</a>.
   *

        Configuration config = smbTreeHandle.getConfig();
        assertNotNull(config, "Configuration should not be null");
        assertEquals(mockConfig, config, "Should return the mock Configuration object");
    }

    /**
     * Test for close() method.
     * Verifies that the close method can be called without throwing an exception.
     * @throws CIFSException
     */
    @Test

Instead, you want to provide a different dependency that will be used only during tests (possibly only some specific tests), and will provide a value that can be used where the value of the original dependency was used.

### Use cases: external service { #use-cases-external-service }

An example could be that you have an external authentication provider that you need to call.

            assertTrue(Modifier.isPublic(modifiers), "Field " + field.getName() + " should be public");
            assertTrue(Modifier.isStatic(modifiers), "Field " + field.getName() + " should be static");
            assertTrue(Modifier.isFinal(modifiers), "Field " + field.getName() + " should be final");
        }
    }

    @Test
    @DisplayName("Test constant values are unique")