*    value (whether it is NaN or infinity).
     * 2. If the new value is finite and the previous mean is non-finite then the mean is unchanged
     *    (whether it is NaN or infinity).
     * 3. If both the previous mean and the new value are non-finite and...
     * 3a. ...either or both is NaN (so mean != value) then the new mean is NaN.

   * the arithmetic mean of the population.
   *
   * <h3>Non-finite values</h3>
   *
   * <p>If the dataset contains {@link Double#NaN} then the result is {@link Double#NaN}. If it
   * contains both {@link Double#POSITIVE_INFINITY} and {@link Double#NEGATIVE_INFINITY} then the
   * result is {@link Double#NaN}. If it contains {@link Double#POSITIVE_INFINITY} and finite values

    } else {
      // This is a generalized version of the calculation in add(double, double) above. Note that
      // non-finite inputs will have sumOfProductsOfDeltas = NaN, so non-finite values will result
      // in NaN naturally.
      sumOfProductsOfDeltas +=
          values.sumOfProductsOfDeltas()
              + (values.xStats().mean() - xStats.mean())
                  * (values.yStats().mean() - yStats.mean())

  }

  public void testMapping_nanY1() {
    assertThrows(
        IllegalArgumentException.class, () -> LinearTransformation.mapping(1.2, Double.NaN));
  }

  public void testMappingAnd_nanX2() {
    assertThrows(
        IllegalArgumentException.class,
        () -> LinearTransformation.mapping(1.2, 3.4).and(Double.NaN, 7.8));
  }

  }

  public void testMapping_nanY1() {
    assertThrows(
        IllegalArgumentException.class, () -> LinearTransformation.mapping(1.2, Double.NaN));
  }

  public void testMappingAnd_nanX2() {
    assertThrows(
        IllegalArgumentException.class,
        () -> LinearTransformation.mapping(1.2, 3.4).and(Double.NaN, 7.8));
  }

    } else {
      // This is a generalized version of the calculation in add(double, double) above. Note that
      // non-finite inputs will have sumOfProductsOfDeltas = NaN, so non-finite values will result
      // in NaN naturally.
      sumOfProductsOfDeltas +=
          values.sumOfProductsOfDeltas()
              + (values.xStats().mean() - xStats.mean())
                  * (values.yStats().mean() - yStats.mean())

        ("-inf", 200),
        ("nan", 200),
        ("0", 200),
        ("342", 200),
    ],
)
def test_allow_inf_nan_param_default(value: str, code: int):
    response = client.post(f"/?z={value}")
    assert response.status_code == code, response.text


@pytest.mark.parametrize(
    "value,code",
    [
        ("-1", 200),
        ("inf", 422),
        ("-inf", 422),
        ("nan", 422),
        ("0", 200),

          .that(Doubles.indexOf(new double[] {5.0, value, value, 5.0}, new double[] {value, value}))
          .isEqualTo(1);
    }
    assertThat(Doubles.indexOf(new double[] {5.0, NaN, NaN, 5.0}, new double[] {NaN, NaN}))
        .isEqualTo(-1);
  }

  public void testLastIndexOf() {
    assertThat(Doubles.lastIndexOf(EMPTY, (double) 1)).isEqualTo(-1);

        assertFalse(DoubleMath.fuzzyEquals(a, Double.NaN, tolerance));
        assertFalse(DoubleMath.fuzzyEquals(Double.NaN, a, tolerance));
      }
    }
  }

  public void testFuzzyEqualsTwoNaNs() {
    for (double tolerance : TOLERANCE_CANDIDATES) {
      assertTrue(DoubleMath.fuzzyEquals(Double.NaN, Double.NaN, tolerance));
    }
  }

  public void testFuzzyEqualsZeroTolerance() {

        assertFalse(DoubleMath.fuzzyEquals(a, Double.NaN, tolerance));
        assertFalse(DoubleMath.fuzzyEquals(Double.NaN, a, tolerance));
      }
    }
  }

  public void testFuzzyEqualsTwoNaNs() {
    for (double tolerance : TOLERANCE_CANDIDATES) {
      assertTrue(DoubleMath.fuzzyEquals(Double.NaN, Double.NaN, tolerance));
    }
  }

  public void testFuzzyEqualsZeroTolerance() {