assertTrue(receivedException.get() instanceof CurlException);
        assertTrue(receivedException.get().getMessage().contains("Failed to access"));
    }

    // --- URL parameter concatenation tests ---

    /**
     * Mock that records the URL it receives.
     */
    class UrlRecordingMockHttpURLConnection extends HttpURLConnection {
        UrlRecordingMockHttpURLConnection(URL u) {

	// since there is no apifmt to format these files.
	// The missing final newline is important for the
	// final release step of cat next/*.txt >go1.X.txt.
	// If the files don't end in full lines, the concatenation goes awry.
	if strings.Contains(s, "\r") {
		log.Printf("%s: contains CRLFs", filename)
		exitCode = 1
	}
	if filepath.Base(filename) == "go1.4.txt" {
		// No use for blank lines in api files, except go1.4.txt

</pre>

<h4 id="String_concatenation">String concatenation</h4>

<p>
Strings can be concatenated using the <code>+</code> operator
or the <code>+=</code> assignment operator:
</p>

<pre>
s := "hi" + string(c)
s += " and good bye"
</pre>

<p>
String addition creates a new string by concatenating the operands.
</p>

    new EqualsTester()
        .addEqualityGroup(Hashing.concatenating(asList(Hashing.md5())))
        .addEqualityGroup(Hashing.concatenating(asList(Hashing.murmur3_32())))
        .addEqualityGroup(
            Hashing.concatenating(Hashing.md5(), Hashing.md5()),
            Hashing.concatenating(asList(Hashing.md5(), Hashing.md5())))
        .addEqualityGroup(
            Hashing.concatenating(Hashing.murmur3_32(), Hashing.md5()),

        decorator.
    *   Added a `tf.keras.layers.experimental.preprocessing.HashedCrossing`
        layer which applies the hashing trick to the concatenation of crossed
        scalar inputs. This provides a stateless way to try adding feature
        crosses of integer or string data to a model.
    *   Removed `keras.layers.experimental.preprocessing.CategoryCrossing`.