Add a test case for the alignment example provided by @FedericoPonzi

Author: DavidGregory084

src/main/java/com/opencastsoftware/prettier4j/Doc.java

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText:  © 2022-2024 Opencast Software Europe Ltd <https://opencastsoftware.com>
+ * SPDX-FileCopyrightText:  © 2022-2025 Opencast Software Europe Ltd <https://opencastsoftware.com>
  * SPDX-License-Identifier: Apache-2.0
  */
 package com.opencastsoftware.prettier4j;
@@ -446,10 +446,10 @@ public String text() {
         @Override
         public Doc append(Doc other) {
             // By string concat equivalency law
-            /*if (other instanceof Text) {
+            if (other instanceof Text) {
                 Text otherText = (Text) other;
                 return text(this.text() + otherText.text());
-            } else*/ if (other instanceof Empty) {
+            } else if (other instanceof Empty) {
                 // By left unit law
                 return this;
             }

src/test/java/com/opencastsoftware/prettier4j/DocTest.java

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText:  © 2022-2024 Opencast Software Europe Ltd <https://opencastsoftware.com>
+ * SPDX-FileCopyrightText:  © 2022-2025 Opencast Software Europe Ltd <https://opencastsoftware.com>
  * SPDX-License-Identifier: Apache-2.0
  */
 package com.opencastsoftware.prettier4j;
@@ -276,6 +276,39 @@ void testNestedBracketFlattening() {
         assertThat(inputDoc.render(20), is(equalTo(expectedWidth20)));
     }
 
+    @Test
+    void testAlignWithMultipleLines() {
+        String expected =
+                "∧ ∨ A ∨ B\n" +
+                "  ∨ C\n" +
+                "∧ ∨ D\n" +
+                "  ∨ E ∧ F\n" +
+                "  ∨ G";
+
+        // (A ∨ B) ∨ C
+        List<Doc> left = List.of(
+                text("A").appendSpace(text("∨")).appendSpace(text("B")),
+                text("C")
+        );
+
+        // D ∨ (E ∧ F) ∨ G
+        List<Doc> right = List.of(
+                text("D"),
+                text("E").appendSpace(text("∧")).appendSpace(text("F")),
+                text("G")
+        );
+
+        Doc alignedLeft = align(text("∨").appendSpace(intersperse(line().append(text("∨ ")), left)));
+        Doc leftJunctions = text("∧").appendSpace(alignedLeft);
+
+        Doc alignedRight = align(text("∨").appendSpace(intersperse(line().append(text("∨ ")), right)));
+        Doc rightJunctions = text("∧").appendSpace(alignedRight);
+
+        String result = leftJunctions.appendLine(rightJunctions).render(80);
+
+        assertThat(result, is(equalTo(expected)));
+    }
+
     @Test
     void testMarginWithLineSeparator() {
         assertThrows(IllegalArgumentException.class, () -> {