test: add empty string and unicode edge cases to ValueTest (#8219)

Author: Tusharika725

api/all/src/test/java/io/opentelemetry/api/logs/ValueFuzzTest.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.api.logs;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import edu.berkeley.cs.jqf.fuzz.Fuzz;
+import edu.berkeley.cs.jqf.fuzz.JQF;
+import edu.berkeley.cs.jqf.fuzz.junit.GuidedFuzzing;
+import edu.berkeley.cs.jqf.fuzz.random.NoGuidance;
+import io.opentelemetry.api.common.Value;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+import org.junit.jupiter.api.Test;
+import org.junit.runner.Result;
+import org.junit.runner.RunWith;
+
+public class ValueFuzzTest {
+  @RunWith(JQF.class)
+  public static class FuzzTestCases {
+    @Fuzz
+    public void valueByteAsStringFuzz(String randomString) {
+      String base64Encoded = Value.of(randomString.getBytes(StandardCharsets.UTF_8)).asString();
+      byte[] decodedBytes = Base64.getDecoder().decode(base64Encoded);
+      assertThat(new String(decodedBytes, StandardCharsets.UTF_8)).isEqualTo(randomString);
+    }
+  }
+
+  @SuppressWarnings("SystemOut")
+  @Test
+  void valueByteAsStringFuzzing() {
+    Result result =
+        GuidedFuzzing.run(
+            FuzzTestCases.class,
+            "valueByteAsStringFuzz",
+            new NoGuidance(10000, System.out),
+            System.out);
+    assertThat(result.wasSuccessful()).isTrue();
+  }
+}

api/all/src/test/java/io/opentelemetry/api/logs/ValueTest.java

@@ -25,6 +25,7 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.jupiter.params.provider.ValueSource;
 
 class ValueTest {
 
@@ -204,12 +205,18 @@ private static Stream<Arguments> asStringArgs() {
         arguments(Value.of("hello world".getBytes(StandardCharsets.UTF_8)), "aGVsbG8gd29ybGQ="));
   }
 
-  @Test
-  void valueByteAsString() {
-    // TODO: add more test cases
-    String str = "hello world";
-    String base64Encoded = Value.of(str.getBytes(StandardCharsets.UTF_8)).asString();
-    byte[] decodedBytes = Base64.getDecoder().decode(base64Encoded);
-    assertThat(new String(decodedBytes, StandardCharsets.UTF_8)).isEqualTo(str);
+  @ParameterizedTest
+  @ValueSource(
+      strings = {
+        "standard string",
+        "special characters !@#$%^&*()",
+        "multi\nline\tstring",
+        "",
+        "emoji boundary test 🚀👩‍💻"
+      })
+  void valueByteAsString(String inputStr) {
+    String base64 = Value.of(inputStr.getBytes(StandardCharsets.UTF_8)).asString();
+    byte[] decoded = Base64.getDecoder().decode(base64);
+    assertThat(new String(decoded, StandardCharsets.UTF_8)).isEqualTo(inputStr);
   }
 }