From dc93ecf3ce4212e69218bd1624ecc9e9a6270871 Mon Sep 17 00:00:00 2001
From: Jesse Squire <jesse.squire@gmail.com>
Date: Fri, 4 Sep 2020 11:01:12 -0400
Subject: [PATCH] [Azure.Core TestFramework] Fix Required Optional Environment
 Variable

The focus of these changes is to bypass the attempt to santitize an optional
environment variable when no value was present.  Previously, if the
variable was not read, sanitizing would result in an exception.
---
 .../src/TestEnvironment.cs                    | 15 ++++++++++----
 .../Azure.Core/tests/TestEnvironmentTests.cs  | 20 ++++++++++++++++++-
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/sdk/core/Azure.Core.TestFramework/src/TestEnvironment.cs b/sdk/core/Azure.Core.TestFramework/src/TestEnvironment.cs
index c2af55787c28..948fbc9249c2 100644
--- a/sdk/core/Azure.Core.TestFramework/src/TestEnvironment.cs
+++ b/sdk/core/Azure.Core.TestFramework/src/TestEnvironment.cs
@@ -177,10 +177,6 @@ protected string GetRecordedOptionalVariable(string name, Action<RecordedVariabl
 
             string value = GetOptionalVariable(name);
 
-            var optionsInstance = new RecordedVariableOptions();
-            options?.Invoke(optionsInstance);
-            var sanitizedValue = optionsInstance.Apply(value);
-
             if (!Mode.HasValue)
             {
                 return value;
@@ -191,6 +187,17 @@ protected string GetRecordedOptionalVariable(string name, Action<RecordedVariabl
                 throw new InvalidOperationException("Recorded value should not be set outside the test method invocation");
             }
 
+            // If the value was populated, sanitize before recording it.
+
+            string sanitizedValue = value;
+
+            if (!string.IsNullOrEmpty(value))
+            {
+                var optionsInstance = new RecordedVariableOptions();
+                options?.Invoke(optionsInstance);
+                sanitizedValue = optionsInstance.Apply(sanitizedValue);
+            }
+
             _recording?.SetVariable(name, sanitizedValue);
             return value;
         }
diff --git a/sdk/core/Azure.Core/tests/TestEnvironmentTests.cs b/sdk/core/Azure.Core/tests/TestEnvironmentTests.cs
index f8151d4abd83..5a52cc0ec84b 100644
--- a/sdk/core/Azure.Core/tests/TestEnvironmentTests.cs
+++ b/sdk/core/Azure.Core/tests/TestEnvironmentTests.cs
@@ -79,6 +79,23 @@ public void RecordedVariableSanitized()
             Assert.AreEqual("endpoint=1;key=Sanitized", testRecording.GetVariable("ConnectionStringWithSecret", ""));
         }
 
+        [Test]
+        public void RecordedOptionalVariableNotSanitizedIfMissing()
+        {
+            var tempFile = Path.GetTempFileName();
+            var env = new MockTestEnvironment();
+            var testRecording = new TestRecording(RecordedTestMode.Record, tempFile, new RecordedTestSanitizer(), new RecordMatcher());
+            env.Mode = RecordedTestMode.Record;
+            env.SetRecording(testRecording);
+
+            Assert.IsNull(env.MissingOptionalSecret);
+
+            testRecording.Dispose();
+            testRecording = new TestRecording(RecordedTestMode.Playback, tempFile, new RecordedTestSanitizer(), new RecordMatcher());
+
+            Assert.IsNull(testRecording.GetVariable(nameof(env.MissingOptionalSecret), null));
+        }
+
         private class RecordedVariableMisuse : RecordedTestBase<MockTestEnvironment>
         {
             // To make NUnit happy
@@ -114,8 +131,9 @@ public MockTestEnvironment(): base("core")
             public string Base64Secret => GetRecordedVariable("Base64Secret", option => option.IsSecret(SanitizedValue.Base64));
             public string DefaultSecret => GetRecordedVariable("DefaultSecret", option => option.IsSecret(SanitizedValue.Default));
             public string CustomSecret => GetRecordedVariable("CustomSecret", option => option.IsSecret("Custom"));
+            public string MissingOptionalSecret => GetRecordedOptionalVariable("MissingOptionalSecret", option => option.IsSecret("INVALID"));
             public string ConnectionStringWithSecret => GetRecordedVariable("ConnectionStringWithSecret", option => option.HasSecretConnectionStringParameter("key"));
 
         }
     }
-}
\ No newline at end of file
+}