added framework for formatting tests, refactored XMLUtilsTest

* added FormattingTest annotation (JUnit tagging)
* added FormattingChecker interface, various implementations for different formatting configurations and a factory to get appropriate implementation
* added formatting options properties sets and multiple executions for Surefire plugin
* refactored XMLUtilsTest: made it a @FormattingTest, removed hacks with classloader

Author: kuzjka

pom.xml

@@ -551,6 +551,80 @@
                         <LANGUAGE>en_US:us</LANGUAGE>
                     </environmentVariables>
                 </configuration>
+                <executions>
+                    <execution>
+                        <id>formatting-ignore-line-breaks</id>
+                        <goals>
+                            <goal>test</goal>
+                        </goals>
+                        <configuration>
+                            <groups>formattingTest</groups>
+                            <systemPropertiesFile>
+                                ${project.build.testOutputDirectory}/formatting/ignore-line-breaks.properties
+                            </systemPropertiesFile>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>formatting-ignore-line-breaks-override</id>
+                        <goals>
+                            <goal>test</goal>
+                        </goals>
+                        <configuration>
+                            <groups>formattingTest</groups>
+                            <systemPropertiesFile>
+                                ${project.build.testOutputDirectory}/formatting/ignore-line-breaks-override.properties
+                            </systemPropertiesFile>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>formatting-ignore-base64-line-breaks</id>
+                        <goals>
+                            <goal>test</goal>
+                        </goals>
+                        <configuration>
+                            <groups>formattingTest</groups>
+                            <systemPropertiesFile>
+                                ${project.build.testOutputDirectory}/formatting/ignore-base64-line-breaks.properties
+                            </systemPropertiesFile>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>formatting-ignore-base64-line-breaks-override</id>
+                        <goals>
+                            <goal>test</goal>
+                        </goals>
+                        <configuration>
+                            <groups>formattingTest</groups>
+                            <systemPropertiesFile>
+                                ${project.build.testOutputDirectory}/formatting/ignore-base64-line-breaks-override.properties
+                            </systemPropertiesFile>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>formatting-base64-custom-formatting</id>
+                        <goals>
+                            <goal>test</goal>
+                        </goals>
+                        <configuration>
+                            <groups>formattingTest</groups>
+                            <systemPropertiesFile>
+                                ${project.build.testOutputDirectory}/formatting/base64-custom-formatting.properties
+                            </systemPropertiesFile>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>formatting-illegal</id>
+                        <goals>
+                            <goal>test</goal>
+                        </goals>
+                        <configuration>
+                            <groups>formattingTest</groups>
+                            <systemPropertiesFile>
+                                ${project.build.testOutputDirectory}/formatting/illegal.properties
+                            </systemPropertiesFile>
+                        </configuration>
+                    </execution>
+                </executions>
             </plugin>
             <plugin>
                 <artifactId>maven-failsafe-plugin</artifactId>

src/test/java/org/apache/xml/security/formatting/CustomBase64FormattingChecker.java

@@ -0,0 +1,74 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.xml.security.formatting;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+
+/**
+ * Checks that XML document is 'pretty-printed', including Base64 values.
+ */
+public class CustomBase64FormattingChecker implements FormattingChecker {
+    private int lineLength;
+    private String lineSeparatorRegex;
+
+    /**
+     * Creates new checker.
+     * @param lineLength            Expected base64 maximum line length
+     * @param lineSeparatorRegex    Regex matching line separator used in Base64 values
+     */
+    public CustomBase64FormattingChecker(int lineLength, String lineSeparatorRegex) {
+        this.lineLength = lineLength;
+        this.lineSeparatorRegex = lineSeparatorRegex;
+    }
+
+    @Override
+    public void checkDocument(String document) {
+        assertThat(document, containsString("\n"));
+    }
+
+    @Override
+    public void checkBase64Value(String value) {
+        String[] lines = value.split(lineSeparatorRegex);
+        if (lines.length == 0) return;
+
+        for (int i = 0; i < lines.length - 1; ++i) {
+            assertThat(lines[i], matchesPattern(BASE64_PATTERN));
+            assertEquals(lineLength, lines[i].length());
+        }
+
+        assertThat(lines[lines.length - 1], matchesPattern(BASE64_PATTERN));
+        assertThat(lines[lines.length - 1].length(), lessThanOrEqualTo(lineLength));
+    }
+
+    @Override
+    public void checkBase64ValueWithSpacing(String value) {
+        /* spacing is added only if the value has multiple lines */
+        if (value.length() <= lineLength) {
+            assertThat(value, matchesRegex(BASE64_PATTERN));
+            return;
+        }
+
+        assertThat(value.length(), greaterThanOrEqualTo(2));
+        assertThat(value, startsWith("\n"));
+        assertThat(value, endsWith("\n"));
+        checkBase64Value(value.substring(1, value.length() - 1));
+    }
+}

src/test/java/org/apache/xml/security/formatting/FormattingChecker.java

@@ -0,0 +1,53 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.xml.security.formatting;
+
+import java.util.regex.Pattern;
+
+/**
+ * Checks document formatting where output depends on formatting options.
+ * Base64 values can be treated in two ways: relatively long values can have additional line breaks
+ * to separate them from element tags.
+ */
+public interface FormattingChecker {
+    /**
+     * This pattern checks if a string contains only characters from the Base64 alphabet, including padding.
+     */
+    Pattern BASE64_PATTERN = Pattern.compile("^[A-Za-z0-9+/=]*$");
+
+    /**
+     * Checks the formatting of the whole document.
+     * @param document  XML document as string
+     *
+     * @implSpec It is assumed that the document contains at least one nested element.
+     */
+    void checkDocument(String document);
+
+    /**
+     * Checks encoded base64 element/attribute value.
+     * @param value Element value
+     */
+    void checkBase64Value(String value);
+
+    /**
+     * Checks encoded base64 element value with additional spacing.
+     * @param value Element value
+     */
+    void checkBase64ValueWithSpacing(String value);
+}

src/test/java/org/apache/xml/security/formatting/FormattingCheckerFactory.java

@@ -0,0 +1,45 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.xml.security.formatting;
+
+/**
+ * Creates formatting checker depending on system properties which define document formatting.
+ */
+public class FormattingCheckerFactory {
+    private static final int DEFAULT_BASE64_LINE_LENGTH = 76;
+
+    /**
+     * Gets formatting checker according to system properties.
+     * @return  Formatting checker implementation
+     */
+    public static FormattingChecker getFormattingChecker() {
+        if (Boolean.getBoolean("org.apache.xml.security.ignoreLineBreaks")) {
+            /* overrides all Base64 formatting options */
+            return new NoLineBreaksChecker();
+        } else if (Boolean.getBoolean("org.apache.xml.security.base64.ignoreLineBreaks")) {
+            return new NoBase64LineBreaksChecker();
+        } else {
+            int lineLength = Integer.getInteger("org.apache.xml.security.base64.lineLength",
+                    DEFAULT_BASE64_LINE_LENGTH);
+            String lineSeparator = System.getProperty("org.apache.xml.security.base64.lineSeparator");
+            String lineSeparatorRegex = "lf".equalsIgnoreCase(lineSeparator) ? "\\n" : "\\r\\n";
+            return new CustomBase64FormattingChecker(lineLength, lineSeparatorRegex);
+        }
+    }
+}

src/test/java/org/apache/xml/security/formatting/FormattingTest.java

@@ -0,0 +1,37 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.xml.security.formatting;
+
+import org.junit.jupiter.api.Tag;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Marks formatting tests which are typically run in different configurations set by system properties.
+ * See {@link org.apache.xml.security.utils.XMLUtils} for formatting options.
+ * Please use {@link FormattingCheckerFactory} to get an appropriate checker for the test.
+ */
+@Target({ElementType.TYPE, ElementType.METHOD})
+@Retention(RetentionPolicy.RUNTIME)
+@Tag("formattingTest")
+public @interface FormattingTest {
+}

src/test/java/org/apache/xml/security/formatting/NoBase64LineBreaksChecker.java

@@ -0,0 +1,43 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.xml.security.formatting;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.matchesPattern;
+
+/**
+ * Checks the document is 'pretty-printed', but base64 values are without line breaks.
+ */
+public class NoBase64LineBreaksChecker implements FormattingChecker {
+    @Override
+    public void checkDocument(String document) {
+        assertThat(document, containsString("\n"));
+    }
+
+    @Override
+    public void checkBase64Value(String value) {
+        assertThat(value, matchesPattern(BASE64_PATTERN));
+    }
+
+    @Override
+    public void checkBase64ValueWithSpacing(String value) {
+        assertThat(value, matchesPattern(BASE64_PATTERN));
+    }
+}

src/test/java/org/apache/xml/security/formatting/NoLineBreaksChecker.java

@@ -0,0 +1,45 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.xml.security.formatting;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.matchesPattern;
+
+/**
+ * Checks there are no line breaks in the document.
+ */
+public class NoLineBreaksChecker implements FormattingChecker {
+    @Override
+    public void checkDocument(String document) {
+        assertThat(document, not(containsString("\n")));
+        assertThat(document, not(containsString("\r")));
+    }
+
+    @Override
+    public void checkBase64Value(String value) {
+        assertThat(value, matchesPattern(BASE64_PATTERN));
+    }
+
+    @Override
+    public void checkBase64ValueWithSpacing(String value) {
+        assertThat(value, matchesPattern(BASE64_PATTERN));
+    }
+}