Cover the two Bruker not-found paths

Both checks changed in this PR are only reachable through BrukerFileReader
directly: MsDataFileReader.GetDataFile rejects a missing path itself, so every
existing test goes through the factory and neither check runs. That left the
DirectoryNotFoundException throw and the analysis.baf FileNotFoundException
throw unhit, and the File.Exists branch half-covered.

Both tests fail against the pre-PR reader - the first saw FileNotFoundException
instead of DirectoryNotFoundException, the second saw a null FileName.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: acesnik

mzLib/Test/FileReadingTests/SpectraFileReading/TestBruker.cs

@@ -392,5 +392,37 @@ public void TestPrecursorChargeStateIsReadFromPerSpectrumVariables()
                 Is.EqualTo(3));
             dynamicReader.CloseDynamicConnection();
         }
+
+        // Both not-found paths have to be reached through the reader directly: MsDataFileReader.GetDataFile
+        // rejects a missing path itself, so going through the factory never runs either check.
+        [Test]
+        public void TestLoadAllStaticDataThrowsWhenTheDotDDirectoryIsMissing()
+        {
+            string missing = Path.Combine(Path.GetTempPath(), "mzLibBrukerMissing_" + Guid.NewGuid().ToString("N") + ".d");
+            var reader = new BrukerFileReader(missing);
+
+            var exception = Assert.Throws<DirectoryNotFoundException>(() => reader.LoadAllStaticData());
+            Assert.That(exception.Message, Does.Contain(missing));
+        }
+
+        // A .d directory that exists but has no analysis.baf: the reader has to say which file is missing
+        // rather than fall through to the native connection with a path it never checked.
+        [Test]
+        public void TestInitiateDynamicConnectionThrowsWhenAnalysisBafIsMissing()
+        {
+            string emptyDotD = Path.Combine(Path.GetTempPath(), "mzLibBrukerEmpty_" + Guid.NewGuid().ToString("N") + ".d");
+            Directory.CreateDirectory(emptyDotD);
+            try
+            {
+                var reader = new BrukerFileReader(emptyDotD);
+
+                var exception = Assert.Throws<FileNotFoundException>(() => reader.InitiateDynamicConnection());
+                Assert.That(exception.FileName, Is.EqualTo(Path.Combine(emptyDotD, "analysis.baf")));
+            }
+            finally
+            {
+                Directory.Delete(emptyDotD, true);
+            }
+        }
     }
 }