test big strings (#3704)

Author: pjfanning

src/test/java/com/fasterxml/jackson/databind/deser/TestBigStrings.java

@@ -0,0 +1,85 @@
+package com.fasterxml.jackson.databind.deser;
+
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.StreamReadConstraints;
+import com.fasterxml.jackson.databind.BaseMapTest;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.json.JsonMapper;
+
+public class TestBigStrings extends BaseMapTest
+{
+    final static class StringWrapper
+    {
+        String string;
+
+        StringWrapper() { }
+
+        StringWrapper(String string) { this.string = string; }
+
+        void setString(String string) {
+            this.string = string;
+        }
+    }
+
+    /*
+    /**********************************************************
+    /* Tests
+    /**********************************************************
+     */
+
+    private final ObjectMapper MAPPER = newJsonMapper();
+
+    private ObjectMapper newJsonMapperWithUnlimitedStringSizeSupport() {
+        JsonFactory jsonFactory = JsonFactory.builder()
+                .streamReadConstraints(StreamReadConstraints.builder().maxStringLength(Integer.MAX_VALUE).build())
+                .build();
+        return JsonMapper.builder(jsonFactory).build();
+    }
+
+    public void testBigString() throws Exception
+    {
+        try {
+            MAPPER.readValue(generateJson("string", 1001000), StringWrapper.class);
+            fail("expected JsonMappingException");
+        } catch (JsonMappingException jsonMappingException) {
+            assertTrue("unexpected exception message: " + jsonMappingException.getMessage(),
+                    jsonMappingException.getMessage().startsWith("String length (1001000) exceeds the maximum length (1000000)"));
+        }
+    }
+
+    public void testBiggerString() throws Exception
+    {
+        try {
+            MAPPER.readValue(generateJson("string", 2000000), StringWrapper.class);
+            fail("expected JsonMappingException");
+        } catch (JsonMappingException jsonMappingException) {
+            final String message = jsonMappingException.getMessage();
+            // this test fails when the TextBuffer is being resized, so we don't yet know just how big the string is
+            // so best not to assert that the String length value in the message is the full 2000000 value
+            assertTrue("unexpected exception message: " + message, message.startsWith("String length"));
+            assertTrue("unexpected exception message: " + message, message.contains("exceeds the maximum length (1000000)"));
+        }
+    }
+
+    public void testUnlimitedString() throws Exception
+    {
+        final int len = 1001000;
+        StringWrapper sw = newJsonMapperWithUnlimitedStringSizeSupport()
+                .readValue(generateJson("string", len), StringWrapper.class);
+        assertEquals(len, sw.string.length());
+    }
+
+
+    private String generateJson(final String fieldName, final int len) {
+        final StringBuilder sb = new StringBuilder();
+        sb.append("{\"")
+                .append(fieldName)
+                .append("\": \"");
+        for (int i = 0; i < len; i++) {
+            sb.append('a');
+        }
+        sb.append("\"}");
+        return sb.toString();
+    }
+}