From 2aa8d73e234ffd91990187e6bd733c5aa514cff1 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Wed, 2 Mar 2016 18:40:00 +0000
Subject: Throw more information exception when attribute is missing

---
 .../zwobble/mammoth/internal/xml/XmlElement.java    |  4 ++--
 .../zwobble/mammoth/tests/xml/XmlElementTests.java  | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 src/test/java/org/zwobble/mammoth/tests/xml/XmlElementTests.java

diff --git a/src/main/java/org/zwobble/mammoth/internal/xml/XmlElement.java b/src/main/java/org/zwobble/mammoth/internal/xml/XmlElement.java
index a0ed784..8b95973 100644
--- a/src/main/java/org/zwobble/mammoth/internal/xml/XmlElement.java
+++ b/src/main/java/org/zwobble/mammoth/internal/xml/XmlElement.java
@@ -30,8 +30,8 @@ public class XmlElement implements XmlNode, XmlElementLike {
     }
 
     public String getAttribute(String name) {
-        // TODO: throw more informative error message
-        return getAttributeOrNone(name).get();
+        return getAttributeOrNone(name)
+            .orElseThrow(() -> new RuntimeException("Element has no '" + name + "' attribute"));
     }
 
     @Override
diff --git a/src/test/java/org/zwobble/mammoth/tests/xml/XmlElementTests.java b/src/test/java/org/zwobble/mammoth/tests/xml/XmlElementTests.java
new file mode 100644
index 0000000..f396b1b
--- /dev/null
+++ b/src/test/java/org/zwobble/mammoth/tests/xml/XmlElementTests.java
@@ -0,0 +1,21 @@
+package org.zwobble.mammoth.tests.xml;
+
+import org.junit.Test;
+import org.zwobble.mammoth.internal.xml.XmlElement;
+import org.zwobble.mammoth.internal.xml.XmlNodes;
+
+import static org.junit.Assert.assertEquals;
+import static org.zwobble.mammoth.tests.util.MammothAsserts.assertThrows;
+
+public class XmlElementTests {
+    @Test
+    public void TryingToGetNonExistentAttributeThrowsException() {
+        XmlElement element = XmlNodes.element("p");
+
+        RuntimeException exception = assertThrows(
+            RuntimeException.class,
+            () -> element.getAttribute("class"));
+
+        assertEquals("Element has no 'class' attribute", exception.getMessage());
+    }
+}
-- 
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