@Test
public void invalidCharactersAreReplacedWithUnderscore() {

	assertThat(PrometheusReporter.replaceInvalidChars(""), equalTo(""));
	assertThat(PrometheusReporter.replaceInvalidChars("abc"), equalTo("abc"));
	assertThat(PrometheusReporter.replaceInvalidChars("abc\""), equalTo("abc_"));
	assertThat(PrometheusReporter.replaceInvalidChars("\"abc"), equalTo("_abc"));
	assertThat(PrometheusReporter.replaceInvalidChars("\"abc\""), equalTo("_abc_"));
	assertThat(PrometheusReporter.replaceInvalidChars("\"a\"b\"c\""), equalTo("_a_b_c_"));
	assertThat(PrometheusReporter.replaceInvalidChars("\"\"\"\""), equalTo("____"));
	assertThat(PrometheusReporter.replaceInvalidChars("    "), equalTo("____"));
	assertThat(PrometheusReporter.replaceInvalidChars("\"ab ;(c)'"), equalTo("_ab___c__"));
	assertThat(PrometheusReporter.replaceInvalidChars("a b c"), equalTo("a_b_c"));
	assertThat(PrometheusReporter.replaceInvalidChars("a b c "), equalTo("a_b_c_"));
	assertThat(PrometheusReporter.replaceInvalidChars("a;b'c*"), equalTo("a_b_c_"));
	assertThat(PrometheusReporter.replaceInvalidChars("a,=;:?'b,=;:?'c"), equalTo("a___:__b___:__c"));
}