diff --git a/core/src/main/java/com/google/zxing/pdf417/encoder/PDF417HighLevelEncoderTestAdapter.java b/core/src/main/java/com/google/zxing/pdf417/encoder/PDF417HighLevelEncoderTestAdapter.java
new file mode 100644
index 000000000..ac6092a52
--- /dev/null
+++ b/core/src/main/java/com/google/zxing/pdf417/encoder/PDF417HighLevelEncoderTestAdapter.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2022 ZXing authors
+ *
+ * Licensed 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 com.google.zxing.pdf417.encoder;
+
+import com.google.zxing.WriterException;
+
+import java.nio.charset.Charset;
+
+/**
+ * Test adapter for PDF417HighLevelEncoder to be called solely from unit tests.
+ */
+
+public final class PDF417HighLevelEncoderTestAdapter {
+
+  private PDF417HighLevelEncoderTestAdapter() {
+  }
+
+  public static String encodeHighLevel(String msg, Compaction compaction, Charset encoding) throws WriterException {
+    return PDF417HighLevelEncoder.encodeHighLevel(msg, compaction, encoding);
+  }
+}
diff --git a/core/src/test/java/com/google/zxing/pdf417/decoder/PDF417DecoderTestCase.java b/core/src/test/java/com/google/zxing/pdf417/decoder/PDF417DecoderTestCase.java
index 50cc9e48f..5f6ac8c08 100644
--- a/core/src/test/java/com/google/zxing/pdf417/decoder/PDF417DecoderTestCase.java
+++ b/core/src/test/java/com/google/zxing/pdf417/decoder/PDF417DecoderTestCase.java
@@ -17,10 +17,16 @@
 package com.google.zxing.pdf417.decoder;
 
 import com.google.zxing.FormatException;
+import com.google.zxing.WriterException;
 import com.google.zxing.pdf417.PDF417ResultMetadata;
 import com.google.zxing.common.DecoderResult;
+import com.google.zxing.pdf417.encoder.Compaction;
+import com.google.zxing.pdf417.encoder.PDF417HighLevelEncoderTestAdapter;
+
 import org.junit.Assert;
 import org.junit.Test;
+import java.nio.charset.StandardCharsets;
+import java.util.Random;
 
 /**
  * Tests {@link DecodedBitStreamParser}.
@@ -175,4 +181,161 @@ public class PDF417DecoderTestCase extends Assert {
     DecodedBitStreamParser.decode(sampleCodes, "0");
   }
 
+  @Test
+  public void testUppercase() throws WriterException, FormatException {
+    //encodeDecode("", 0);
+    performEncodeTest('A', new int[] { 3, 4, 5, 6, 4, 4, 5, 5});
+  }
+
+  @Test
+  public void testNumeric() throws WriterException, FormatException {
+    performEncodeTest('1', new int[] { 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10});
+  }
+
+  @Test
+  public void testByte() throws WriterException, FormatException {
+    performEncodeTest('\u00c4', new int[] { 3, 4, 5, 6, 7, 7, 8});
+  }
+
+  @Test
+  public void testUppercaseLowercaseMix1() throws WriterException, FormatException {
+    encodeDecode("aA", 4);
+    encodeDecode("aAa", 5);
+    encodeDecode("Aa", 4);
+    encodeDecode("Aaa", 5);
+    encodeDecode("AaA", 5);
+    encodeDecode("AaaA", 6);
+    encodeDecode("Aaaa", 6);
+    encodeDecode("AaAaA", 5);
+    encodeDecode("AaaAaaA", 6);
+    encodeDecode("AaaAAaaA", 7);
+  }
+
+  @Test
+  public void testPunctuation() throws WriterException, FormatException {
+    performEncodeTest(';', new int[] { 3, 4, 5, 6, 6, 7, 8});
+    encodeDecode(";;;;;;;;;;;;;;;;", 17);
+  }
+
+  @Test
+  public void testUppercaseLowercaseMix2() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'A', 'a'}, 10, 8972);
+  }
+
+  @Test
+  public void testUppercaseNumericMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'A', '1'}, 14, 192510);
+  }
+
+  @Test
+  public void testUppercaseMixedMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'A', '1', ' ', ';'}, 7, 106060);
+  }
+
+  @Test
+  public void testUppercasePunctuationMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'A', ';'}, 10, 8967);
+  }
+
+  @Test
+  public void testUppercaseByteMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'A', '\u00c4'}, 10, 11222);
+  }
+
+  @Test
+  public void testLowercaseByteMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'a', '\u00c4'}, 10, 11233);
+  }
+
+  public void testUppercaseLowercaseNumericMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'A', 'a', '1'}, 7, 15491);
+  }
+
+  @Test
+  public void testUppercaseLowercasePunctuationMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'A', 'a', ';'}, 7, 15491);
+  }
+
+  @Test
+  public void testUppercaseLowercaseByteMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'A', 'a', '\u00c4'}, 7, 17288);
+  }
+
+  @Test
+  public void testLowercasePunctuationByteMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'a', ';', '\u00c4'}, 7, 17427);
+  }
+
+  @Test
+  public void testUppercaseLowercaseNumericPunctuationMix() throws WriterException, FormatException {
+    performPermutationTest(new char[] {'A', 'a', '1', ';'}, 7, 120479);
+  }
+
+  @Test
+  public void testBinaryData() throws WriterException, FormatException {
+    byte[] bytes = new byte[500];
+    Random random = new Random(0);
+    int total = 0;
+    for (int i = 0; i < 10000; i++) {
+      random.nextBytes(bytes);
+      total += encodeDecode(new String(bytes, StandardCharsets.ISO_8859_1));
+    }
+    assertEquals(4190044, total); 
+  }
+
+  private static void encodeDecode(String input, int expectedLength) throws WriterException, FormatException {
+    assertEquals(expectedLength, encodeDecode(input));
+  }
+
+  private static int encodeDecode(String input) throws WriterException, FormatException {
+    String s = PDF417HighLevelEncoderTestAdapter.encodeHighLevel(input, Compaction.AUTO, null);
+    int[] codewords = new int[s.length() + 1];
+    codewords[0] = codewords.length;
+    for (int i = 1; i < codewords.length; i++) {
+      codewords[i] = s.charAt(i - 1);
+    }
+    DecoderResult result = DecodedBitStreamParser.decode(codewords, "0");
+
+    assertEquals(input, result.getText());
+    return codewords.length;
+  }
+
+  private static int getEndIndex(int length, char[] chars) {
+    double decimalLength = Math.log10(chars.length);
+    return (int) Math.ceil(Math.pow(10, decimalLength * length));
+  }
+
+  private static String generatePermutation(int index, int length, char[] chars) {
+    int N = chars.length;
+    String baseNNumber = Integer.toString(index, N);
+    while (baseNNumber.length() < length) {
+      baseNNumber = "0" + baseNNumber;
+    }
+    String prefix = "";
+    for (int i = 0; i < baseNNumber.length(); i++) {
+      prefix += chars[baseNNumber.charAt(i) - '0'];
+    }
+    return prefix;
+  }
+
+  private static void performPermutationTest(char[] chars, int length, int expectedTotal) throws WriterException,
+      FormatException {
+    int endIndex = getEndIndex(length, chars);
+    int total = 0;
+    for (int i = 0; i < endIndex; i++) {
+      total += encodeDecode(generatePermutation(i, length, chars));
+    }
+    assertEquals(expectedTotal, total);
+  }
+
+  private static void performEncodeTest(char c, int[] expectedLengths) throws WriterException, FormatException {
+    for (int i = 0; i < expectedLengths.length; i++) {
+      StringBuilder sb = new StringBuilder();
+      for (int j = 0; j <= i; j++) {
+        sb.append(c);
+      }
+      encodeDecode(sb.toString(), expectedLengths[i]);
+    }
+  }
+
 }