diff --git a/src/main/java/ghast/logger/StringFormatter.java b/src/main/java/ghast/logger/StringFormatter.java
index bde0513..1e1f530 100644
--- a/src/main/java/ghast/logger/StringFormatter.java
+++ b/src/main/java/ghast/logger/StringFormatter.java
@@ -13,7 +13,7 @@ public final class StringFormatter {
     private static final char ESCAPE_CHAR = '\\';
 
     public static String arrayFormat(String messagePattern, Object[] argArray) {
-        if (messagePattern == null) {
+        if (messagePattern == null || messagePattern.equals(EMPTY)) {
             return EMPTY;
         } else if (argArray == null) {
             return messagePattern;
@@ -30,7 +30,7 @@ public final class StringFormatter {
                 if (k == 0) { // this is a simple string
                     return messagePattern;
                 } else { // add the tail string which contains no variables and return
-                    // the result.
+                         // the result.
                     sb.append(messagePattern, k, messagePattern.length());
                     return sb.toString();
                 }
diff --git a/src/test/java/ghast/logger/StringFormatterTest.java b/src/test/java/ghast/logger/StringFormatterTest.java
new file mode 100644
index 0000000..33ed046
--- /dev/null
+++ b/src/test/java/ghast/logger/StringFormatterTest.java
@@ -0,0 +1,95 @@
+package ghast.logger;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class StringFormatterTest {
+
+    @Test
+    void emptyPattern() {
+        String actual = StringFormatter.arrayFormat(null, null);
+        assertEquals("", actual);
+
+        actual = StringFormatter.arrayFormat("", null);
+        assertEquals("", actual);
+    }
+
+    @Test
+    void nullArgArray() {
+        String pattern = "some pattern";
+        String actual = StringFormatter.arrayFormat(pattern, null);
+        assertEquals(pattern, actual);
+
+        pattern = "some pattern {}";
+        actual = StringFormatter.arrayFormat(pattern, null);
+        assertEquals(pattern, actual);
+    }
+
+    @Test
+    void dummyPattern() {
+        String actual = StringFormatter.arrayFormat("dummy pattern", new Object[]{"argument"});
+        assertEquals("dummy pattern", actual);
+    }
+
+    @Test
+    void escapePattern() {
+        String actual = StringFormatter.arrayFormat("Arg1: \\{}", new Object[]{"item1"});
+        assertEquals("Arg1: {}", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}, \\{}", new Object[]{"item1"});
+        assertEquals("Arg1: item1, \\{}", actual);
+    }
+
+    @Test
+    void simpleArg() {
+        String actual;
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{"item1"});
+        assertEquals("Arg1: item1", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{11});
+        assertEquals("Arg1: 11", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{11.5f});
+        assertEquals("Arg1: 11.5", actual);
+    }
+
+    @Test
+    void nullArg() {
+        String actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{null});
+        assertEquals("Arg1: null", actual);
+    }
+
+    @Test
+    void arrayArg() {
+        String actual;
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{new boolean[]{false, true}});
+        assertEquals("Arg1: [false, true]", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{new byte[]{0b00, 0b01}});
+        assertEquals("Arg1: [0, 1]", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{new char[]{'c', 'h'}});
+        assertEquals("Arg1: [c, h]", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{new short[]{11, 12}});
+        assertEquals("Arg1: [11, 12]", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{new int[]{11, 12}});
+        assertEquals("Arg1: [11, 12]", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{new long[]{11L, 12L}});
+        assertEquals("Arg1: [11, 12]", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{new float[]{11.2f, 12.3f}});
+        assertEquals("Arg1: [11.2, 12.3]", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{new double[]{11.2d, 12.3d}});
+        assertEquals("Arg1: [11.2, 12.3]", actual);
+
+        actual = StringFormatter.arrayFormat("Arg1: {}", new Object[]{new String[]{"str-arr-1", "str-arr-2"}});
+        assertEquals("Arg1: [str-arr-1, str-arr-2]", actual);
+    }
+}
\ No newline at end of file