diff --git a/src/jes/core/encoding.d b/src/jes/core/encoding.d
index 32a6a0d..230c438 100644
--- a/src/jes/core/encoding.d
+++ b/src/jes/core/encoding.d
@@ -138,4 +138,48 @@ struct Encoding
         }
         return (20u * n_high_zeros / n) != 0u;
     }
+
+    unittest
+    {
+        import std.stdio;
+        import std.file;
+        const(ubyte)[] dat;
+        Encoding e;
+        size_t bom_size;
+
+        dat = cast(const(ubyte)[])std.file.read("test/files/encodings/utf-8.txt");
+        e = Encoding.detect_encoding(dat.ptr, dat.length, &bom_size);
+        assert(e == Encoding.UTF8);
+        assert(bom_size == 0u);
+
+        dat = cast(const(ubyte)[])std.file.read("test/files/encodings/utf-8-bom.txt");
+        e = Encoding.detect_encoding(dat.ptr, dat.length, &bom_size);
+        assert(e == Encoding.UTF8);
+        assert(bom_size == 3u);
+
+        dat = cast(const(ubyte)[])std.file.read("test/files/encodings/utf-16le.txt");
+        e = Encoding.detect_encoding(dat.ptr, dat.length, &bom_size);
+        assert(e == Encoding.UTF16_LE);
+        assert(bom_size == 2u);
+
+        dat = cast(const(ubyte)[])std.file.read("test/files/encodings/utf-16le-nobom.txt");
+        e = Encoding.detect_encoding(dat.ptr, dat.length, &bom_size);
+        assert(e == Encoding.UTF16_LE);
+        assert(bom_size == 0u);
+
+        dat = cast(const(ubyte)[])std.file.read("test/files/encodings/utf-16be.txt");
+        e = Encoding.detect_encoding(dat.ptr, dat.length, &bom_size);
+        assert(e == Encoding.UTF16_BE);
+        assert(bom_size == 2u);
+
+        dat = cast(const(ubyte)[])std.file.read("test/files/encodings/utf-16be-nobom.txt");
+        e = Encoding.detect_encoding(dat.ptr, dat.length, &bom_size);
+        assert(e == Encoding.UTF16_BE);
+        assert(bom_size == 0u);
+
+        dat = cast(const(ubyte)[])std.file.read("test/files/encodings/cp-1252.txt");
+        e = Encoding.detect_encoding(dat.ptr, dat.length, &bom_size);
+        assert(e == Encoding.CP1252);
+        assert(bom_size == 0u);
+    }
 };