.url(server.url("/"))
          .build(),
      )
    val response1 = call1.execute()
    assertThat(response1.body.string()).isEqualTo("abc")
    response1.close()

    // Force a fresh connection for the next request.
    client.connectionPool.evictAll()

    // Confirm that a second request also succeeds. This should detect caching problems.
    server.enqueue(
      MockResponse

      Object instance = ArbitraryInstances.get(mutableClass);
      assertNotNull("Expected to return non-null for: " + mutableClass, instance);
      assertNotSame(
          "Expected to return fresh instance for: " + mutableClass,
          instance,
          ArbitraryInstances.get(mutableClass));
    }
  }

  private enum EmptyEnum {}

  private enum Direction {
    UP,
    DOWN
  }

 * Immutable empty instances are returned for collection types; {@code ""} for string; {@code 0} for
 * number types; reasonable default instance for other stateless types. For mutable types, a fresh
 * instance is created each time {@code get()} is called.
 *
 * @author Kevin Bourrillion
 * @author Ben Yu
 * @since 12.0
 */
@GwtIncompatible
@J2ktIncompatible
@NullMarked

      }
    }
    resizeMeMaybe(newSize);
    insertEntry(newEntryIndex, object, hash, mask);
    this.size = newSize;
    incrementModCount();
    return true;
  }

  /**
   * Creates a fresh entry with the specified object at the specified position in the entry arrays.
   */
  void insertEntry(int entryIndex, @ParametricNullness E object, int hash, int mask) {

      segmentSize <<= 1;
    }

    for (int i = 0; i < this.segments.length; ++i) {
      this.segments[i] = createSegment(segmentSize);
    }
  }

  /** Returns a fresh {@link MapMakerInternalMap} as specified by the given {@code builder}. */
  static <K, V> MapMakerInternalMap<K, V, ? extends InternalEntry<K, V, ?>, ?> create(
      MapMaker builder) {

     * @param host an IP address or hostname.
     * @param port the IP port associated with the service.
     * @param maxAge time in seconds that this alternative is considered fresh.
     */
    fun alternateService(
      streamId: Int,
      origin: String,
      protocol: ByteString,
      host: String,
      port: Int,
      maxAge: Long,
    )
  }

    }
  }

  private enum LinkedListSupplier implements Supplier<List<?>> {
    INSTANCE;

    static <V extends @Nullable Object> Supplier<List<V>> instance() {
      // Each call generates a fresh LinkedList, which can serve as a List<V> for any V.
      @SuppressWarnings({"rawtypes", "unchecked"})
      Supplier<List<V>> result = (Supplier) INSTANCE;
      return result;
    }

    @Override

    }
  }

  private enum LinkedListSupplier implements Supplier<List<?>> {
    INSTANCE;

    static <V extends @Nullable Object> Supplier<List<V>> instance() {
      // Each call generates a fresh LinkedList, which can serve as a List<V> for any V.
      @SuppressWarnings({"rawtypes", "unchecked"})
      Supplier<List<V>> result = (Supplier) INSTANCE;
      return result;
    }

    @Override

And if you update that local FastAPI source code when you run that Python file again, it will use the fresh version of FastAPI you just edited.

That way, you don't have to "install" your local version to be able to test every change.

/// note | Technical Details

    // Stalling the socket will cause TWO requests to time out!
    server.enqueue(MockResponse.Builder().onRequestStart(Stall).build())

    // The 3rd request should be sent to a fresh connection.
    server.enqueue(
      MockResponse(body = "fresh connection"),
    )

    // The first call times out.
    val call1 = client.newCall(Request(server.url("/")))
    assertFailsWith<IOException> {
      call1.execute()