Freshsales integration (#1782)

* Add FreshsalesController

* Add better errors

* Fix formatting issues

* Add comments

* Add Billing.Test to solution files

* Fix unit test

* Format code

* Address PR feedback

test/Common/AutoFixture/Attributes/EnvironmentDataAttribute.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using Xunit.Sdk;
+
+namespace Bit.Test.Common.AutoFixture.Attributes
+{
+    /// <summary>
+    /// Used for collecting data from environment useful for when we want to test an integration with another service and
+    /// it might require an api key or other piece of sensitive data that we don't want slipping into the wrong hands.
+    /// </summary>
+    /// <remarks>
+    /// It probably should be refactored to support fixtures and other customization so it can more easily be used in conjunction
+    /// with more parameters.  Currently it attempt to match environment variable names to values of the parameter type in that positions.
+    /// It will start from the first parameter and go for each supplied name.
+    /// </remarks>
+    public class EnvironmentDataAttribute : DataAttribute
+    {
+        private readonly string[] _environmentVariableNames;
+
+        public EnvironmentDataAttribute(params string[] environmentVariableNames)
+        {
+            _environmentVariableNames = environmentVariableNames;
+        }
+
+        public override IEnumerable<object[]> GetData(MethodInfo testMethod)
+        {
+            var methodParameters = testMethod.GetParameters();
+
+            if (methodParameters.Length < _environmentVariableNames.Length)
+            {
+                throw new ArgumentException($"The target test method only has {methodParameters.Length} arguments but you supplied {_environmentVariableNames.Length}");
+            }
+
+            var values = new object[_environmentVariableNames.Length];
+
+            for (var i = 0; i < _environmentVariableNames.Length; i++)
+            {
+                values[i] = Convert.ChangeType(Environment.GetEnvironmentVariable(_environmentVariableNames[i]), methodParameters[i].ParameterType);
+            }
+
+            return new[] { values };
+        }
+    }
+}

test/Common/AutoFixture/Attributes/RequiredEnvironmentTheoryAttribute.cs

@@ -0,0 +1,39 @@
+using System;
+using Xunit;
+
+namespace Bit.Test.Common.AutoFixture.Attributes
+{
+    /// <summary>
+    /// Used for requiring certain environment variables exist at the time. Mostly used for more edge unit tests that shouldn't
+    /// be run during CI builds or should only be ran in CI builds when pieces of information are available.
+    /// </summary>
+    public class RequiredEnvironmentTheoryAttribute : TheoryAttribute
+    {
+        private readonly string[] _environmentVariableNames;
+
+        public RequiredEnvironmentTheoryAttribute(params string[] environmentVariableNames)
+        {
+            _environmentVariableNames = environmentVariableNames;
+
+            if (!HasRequiredEnvironmentVariables())
+            {
+                Skip = $"Missing one or more required environment variables. ({string.Join(", ", _environmentVariableNames)})";
+            }
+        }
+
+        private bool HasRequiredEnvironmentVariables()
+        {
+            foreach (var env in _environmentVariableNames)
+            {
+                var value = Environment.GetEnvironmentVariable(env);
+
+                if (value == null)
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+    }
+}