Create TestFileUtils.getMD5Hash to compare binary files

Don't use `Files.readString` to read non-text files

Author: labkey-tchad

src/org/labkey/test/TestFileUtils.java

@@ -64,6 +64,8 @@
 import java.nio.file.Paths;
 import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 import java.security.Security;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -105,6 +107,9 @@ public static String getFileContents(final File file)
         return getFileContents(path);
     }
 
+    /**
+     * Get text content of a file. Will throw an error for non-text files (e.g. PDF).
+     */
     public static String getFileContents(Path path)
     {
         try
@@ -117,6 +122,21 @@ public static String getFileContents(Path path)
         }
     }
 
+    /**
+     * Compute MD5 hash for the given file. Useful checking file equivalence.
+     */
+    public static String getMD5Hash(Path path)
+    {
+        try
+        {
+            return new String(MessageDigest.getInstance("MD5").digest(Files.readAllBytes(path)), StandardCharsets.UTF_8);
+        }
+        catch (IOException | NoSuchAlgorithmException fail)
+        {
+            throw new RuntimeException(fail);
+        }
+    }
+
     public static String getStreamContentsAsString(InputStream is) throws IOException
     {
         return StringUtils.join(IOUtils.readLines(is, Charset.defaultCharset()).toArray(), System.lineSeparator());

src/org/labkey/test/tests/FileAttachmentColumnTest.java

@@ -550,9 +550,9 @@ private void validateSampleData(String sampleType, String folderPath, List<File>
                  {
                      // verify fie download behavior
                      File downloadedFile = doAndWaitForDownload(() -> optionalFileLink.get().click());
-                     checker().wrapAssertion(() -> Assertions.assertThat(TestFileUtils.getFileContents(downloadedFile))
+                     checker().wrapAssertion(() -> Assertions.assertThat(TestFileUtils.getMD5Hash(downloadedFile.toPath()))
                              .as("expect the downloaded file to be the expected file")
-                             .isEqualTo(TestFileUtils.getFileContents(file)));   // guard against renames like file2.xyz
+                             .isEqualTo(TestFileUtils.getMD5Hash(file.toPath())));   // guard against renames like file2.xyz
                  }
             }
         }
@@ -576,9 +576,9 @@ private void validateAssayRun(String assayName, String folderPath, String runNam
         if (optionalFileLink.isPresent())
         {
             var file = doAndWaitForDownload(()-> optionalFileLink.get().click());
-            checker().wrapAssertion(()-> Assertions.assertThat(TestFileUtils.getFileContents(file))
+            checker().wrapAssertion(()-> Assertions.assertThat(TestFileUtils.getMD5Hash(file.toPath()))
                     .as("expect the downloaded file to have equivalent content")
-                    .isEqualTo(TestFileUtils.getFileContents(runFile)));
+                    .isEqualTo(TestFileUtils.getMD5Hash(runFile.toPath())));
         }
 
         var resultsPage = runsPage.clickAssayIdLink(runName);
@@ -644,9 +644,9 @@ private void validateDatasetData(String datasetName, String folderPath, List<Fil
                 {
                     // verify fie download behavior
                     File downloadedFile = doAndWaitForDownload(() -> optionalFileLink.get().click());
-                    checker().wrapAssertion(() -> Assertions.assertThat(TestFileUtils.getFileContents(downloadedFile))
+                    checker().wrapAssertion(() -> Assertions.assertThat(TestFileUtils.getMD5Hash(downloadedFile.toPath()))
                             .as("expect the downloaded file to be the expected file")
-                            .isEqualTo(TestFileUtils.getFileContents(file)));   // guard against renames like file2.xyz
+                            .isEqualTo(TestFileUtils.getMD5Hash(file.toPath())));   // guard against renames like file2.xyz
                 }
             }
         }