Fix other tests

Author: tobias-tengler

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpExporterOptionsExtensions.cs

@@ -36,13 +36,27 @@ public static IReadOnlyDictionary<string, string> GetHeaders(this OtlpExporterOp
 
             if (nextEqualIndex == -1)
             {
-                throw new ArgumentException("Headers provided in an invalid format.");
+                throw CreateInvalidHeaderFormatException();
+            }
+
+            // Skip any leading commas.
+            var leadingCommaIndex = headersSpan.Slice(0, nextEqualIndex).LastIndexOf(',');
+            if (leadingCommaIndex != -1)
+            {
+                headersSpan = headersSpan.Slice(leadingCommaIndex + 1);
+                nextEqualIndex -= leadingCommaIndex + 1;
             }
 
             while (!headersSpan.IsEmpty)
             {
                 var key = headersSpan.Slice(0, nextEqualIndex).Trim().ToString();
 
+                // HTTP header field-names can not be empty: https://www.rfc-editor.org/rfc/rfc7230#section-3.2
+                if (key.Length < 1)
+                {
+                    throw CreateInvalidHeaderFormatException();
+                }
+
                 headersSpan = headersSpan.Slice(nextEqualIndex + 1);
 
                 nextEqualIndex = headersSpan.IndexOf('=');
@@ -51,7 +65,7 @@ public static IReadOnlyDictionary<string, string> GetHeaders(this OtlpExporterOp
                 if (nextEqualIndex == -1)
                 {
                     // Everything until the end of the string can be considered the value.
-                    value = headersSpan.Trim().ToString();
+                    value = headersSpan.TrimEnd(',').Trim().ToString();
                     headersSpan = [];
                 }
                 else
@@ -63,12 +77,12 @@ public static IReadOnlyDictionary<string, string> GetHeaders(this OtlpExporterOp
 
                     if (lastComma == -1)
                     {
-                        throw new ArgumentException("Headers provided in an invalid format.");
+                        throw CreateInvalidHeaderFormatException();
                     }
 
                     potentialValue = potentialValue.Slice(0, lastComma);
 
-                    value = potentialValue.Trim().ToString();
+                    value = potentialValue.TrimEnd(',').Trim().ToString();
                     headersSpan = headersSpan.Slice(lastComma + 1);
                     nextEqualIndex -= potentialValue.Length + 1;
                 }
@@ -85,6 +99,9 @@ public static IReadOnlyDictionary<string, string> GetHeaders(this OtlpExporterOp
         return headers;
     }
 
+    private static ArgumentException CreateInvalidHeaderFormatException()
+        => new("Headers provided in an invalid format. Use: header=value,header=value");
+
     public static OtlpExporterTransmissionHandler GetExportTransmissionHandler(this OtlpExporterOptions options, ExperimentalOptions experimentalOptions, OtlpSignalType otlpSignalType)
     {
         var exportClient = GetExportClient(options, otlpSignalType);

test/OpenTelemetry.Exporter.OpenTelemetryProtocol.Tests/OtlpExporterOptionsExtensionsTests.cs

@@ -36,8 +36,8 @@ public void GetHeaders_NoOptionHeaders_ReturnsStandardHeaders(string? optionHead
 
     [Theory]
     [InlineData(" ")]
-    [InlineData(",key1=value1,key2=value2,")]
-    [InlineData(",,key1=value1,,key2=value2,,")]
+    [InlineData(",")]
+    [InlineData("=value1")]
     [InlineData("key1")]
     public void GetHeaders_InvalidOptionHeaders_ThrowsArgumentException(string inputOptionHeaders)
     {
@@ -53,12 +53,13 @@ public void GetHeaders_InvalidOptionHeaders_ThrowsArgumentException(string input
     [InlineData("key1=value1,value2,key2=value3", "key1=value1,value2,key2=value3")]
     [InlineData(" key1 = value1 , key2=value2 ", "key1=value1,key2=value2")]
     [InlineData("key1= value with spaces ,key2=another value", "key1=value with spaces,key2=another value")]
-    [InlineData("=value1", "=value1")]
     [InlineData("key1=", "key1=")]
     [InlineData("key1=value1%2Ckey2=value2", "key1=value1,key2=value2")]
     [InlineData("key1=value1%2Ckey2=value2%2Ckey3=value3", "key1=value1,key2=value2,key3=value3")]
     [InlineData("key1=value1%2Cvalue2", "key1=value1,value2")]
     [InlineData("key1=value1%2Cvalue2%2Ckey2=value3", "key1=value1,value2,key2=value3")]
+    [InlineData(",key1=value1,key2=value2,", "key1=value1,key2=value2")]
+    [InlineData(",,key1=value1,,key2=value2,,", "key1=value1,key2=value2")]
     public void GetHeaders_ValidAndUrlEncodedHeaders_ReturnsCorrectHeaders(string inputOptionHeaders, string expectedNormalizedOptional)
     {
         VerifyHeaders(inputOptionHeaders, expectedNormalizedOptional);