Baggage format parsing tests

Author: nblumhardt

src/Serilog.Sinks.OpenTelemetry/Sinks/OpenTelemetry/Configuration/BaggageFormat.cs

@@ -12,17 +12,19 @@ static class BaggageFormat
         // See: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/resource/sdk.md#specifying-resource-information-via-an-environment-variable
         // See: https://www.w3.org/TR/baggage/#header-content
 
+        if (string.IsNullOrWhiteSpace(baggageString)) yield break;
+        
         foreach (var listMember in baggageString.Split(','))
         {
             // The baggage spec allows list members to carry additional key-value pair metadata after the initial
             // key and value and a trailing semicolon, but this is disallowed by the OTel spec. We're pretty loose with
             // validation, here, but could tighten up handling of invalid values in the future.
 
             var eq = listMember.IndexOf('=');
-            if (eq == -1) RejectInvalidListMember(listMember, environmentVariableName);
+            if (eq == -1) RejectInvalidListMember(listMember, environmentVariableName, nameof(baggageString));
 
             var key = listMember.Substring(0, eq).Trim();
-            if (string.IsNullOrEmpty(key)) RejectInvalidListMember(listMember, environmentVariableName);
+            if (string.IsNullOrEmpty(key)) RejectInvalidListMember(listMember, environmentVariableName, nameof(baggageString));
 
             var escapedValue = eq == listMember.Length - 1 ? "" : listMember.Substring(eq + 1).Trim();
             var value = Uri.UnescapeDataString(escapedValue);
@@ -31,8 +33,8 @@ static class BaggageFormat
         }
     }
 
-    static void RejectInvalidListMember(string listMember, string environmentVariableName)
+    static void RejectInvalidListMember(string listMember, string environmentVariableName, string paramName)
     {
-        throw new InvalidOperationException($"Invalid item format `{listMember}` in {environmentVariableName} environment variable.");
+        throw new ArgumentException($"Invalid item format `{listMember}` in {environmentVariableName} environment variable.", paramName);
     }
 }

test/Serilog.Sinks.OpenTelemetry.Tests/BaggageFormatTests.cs

@@ -0,0 +1,37 @@
+using Serilog.Sinks.OpenTelemetry.Configuration;
+using Serilog.Sinks.OpenTelemetry.Tests.Support;
+using Xunit;
+
+namespace Serilog.Sinks.OpenTelemetry.Tests;
+
+public class BaggageFormatTests
+{
+    public static TheoryData<string, (string, string)[]> Cases => new()
+    {
+        { "", [] },
+        { " ", [] },
+        { "a=", [("a", "")] },
+        { "abc=def", [("abc", "def")] },
+        { "abc= def ", [("abc", "def")] },
+        { "abc=def,ghi=jkl", [("abc", "def"), ("ghi", "jkl")] },
+        { "a=1%202", [("a", "1 2")] },
+    };
+    
+    [Theory, MemberData(nameof(Cases))]
+    public void BaggageStringsAreDecoded(string baggageString, IEnumerable<(string, string)> expected)
+    {
+        var actual = BaggageFormat.DecodeBaggageString(baggageString, Some.String());
+        Assert.Equal(expected, actual);
+    }
+
+    [Theory]
+    [InlineData(",")]
+    [InlineData(", ")]
+    [InlineData("a")]
+    [InlineData("=")]
+    [InlineData(",=")]
+    public void InvalidBaggageStringsAreRejected(string baggageString)
+    {
+        Assert.Throws<ArgumentException>(() => BaggageFormat.DecodeBaggageString(baggageString, Some.String()).ToList());
+    }
+}

test/Serilog.Sinks.OpenTelemetry.Tests/OpenTelemetryEnvironmentTests.cs

@@ -88,9 +88,9 @@ public void ConfigureThrowsIfHeaderEnvIsInvalidFormat()
         BatchedOpenTelemetrySinkOptions options = new();
         var headers = "header1";
 
-        var exception = Assert.Throws<InvalidOperationException>(() => OpenTelemetryEnvironment.Configure(options, GetEnvVar));
+        var exception = Assert.Throws<ArgumentException>(() => OpenTelemetryEnvironment.Configure(options, GetEnvVar));
 
-        Assert.Equal("Invalid item format `header1` in OTEL_EXPORTER_OTLP_HEADERS environment variable.", exception.Message);
+        Assert.StartsWith("Invalid item format `header1` in OTEL_EXPORTER_OTLP_HEADERS environment variable.", exception.Message);
 
         string? GetEnvVar(string name)
              => name switch
@@ -106,9 +106,9 @@ public void ConfigureThrowsIfResourceAttributesEnvIsInvalidFormat()
         BatchedOpenTelemetrySinkOptions options = new();
         var resourceAttributes = "resource1";
 
-        var exception = Assert.Throws<InvalidOperationException>(() => OpenTelemetryEnvironment.Configure(options, GetEnvVar));
+        var exception = Assert.Throws<ArgumentException>(() => OpenTelemetryEnvironment.Configure(options, GetEnvVar));
 
-        Assert.Equal("Invalid item format `resource1` in OTEL_RESOURCE_ATTRIBUTES environment variable.", exception.Message);
+        Assert.StartsWith("Invalid item format `resource1` in OTEL_RESOURCE_ATTRIBUTES environment variable.", exception.Message);
 
         string? GetEnvVar(string name)
              => name switch