Update tests and CreateAar

Author: dellis1972

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.AndroidLibraries.targets

@@ -77,6 +77,7 @@ projects.
       Outputs="$(_AarOutputPath)">
     <CreateAar
         AssetDirectory="$(MonoAndroidAssetsPrefix)"
+        PrefixProperty="MonoAndroidAssetsPrefix"
         AndroidAssets="@(AndroidAsset)"
         AndroidResources="@(_AndroidResourceDest)"
         AndroidEnvironment="@(AndroidEnvironment)"

src/Xamarin.Android.Build.Tasks/Tasks/CreateAar.cs

@@ -34,8 +34,14 @@ public class CreateAar : AndroidTask
 		[Required]
 		public string OutputFile { get; set; }
 
+		public string PrefixProperty { get; set; }
+
 		public override bool RunTask ()
 		{
+			if (Path.IsPathRooted (AssetDirectory)) {
+				Log.LogCodedError ("XA1041", message: Properties.Resources.XA1041, PrefixProperty, AssetDirectory);
+				return false;
+			}
 			Directory.CreateDirectory (Path.GetDirectoryName (OutputFile));
 
 			using (var stream = File.Create (OutputFile))

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildAssetsTest.cs

@@ -181,7 +181,9 @@ public void FullPath ()
 
 		[Test]
 		[Category ("SmokeTests")]
-		public void FullAssetPathRaisesError()
+		[TestCase("MonoAndroidAssetsPrefix")]
+		[TestCase("MonoAndroidResourcePrefix")]
+		public void FullPrefixRaisesError(string prefix)
 		{
 			var proj = new XamarinAndroidLibraryProject {
 				OtherBuildItems = {
@@ -200,16 +202,14 @@ public void FullAssetPathRaisesError()
 					},
 				},
 			};
-			var envar = new Dictionary<string, string> {
-				{ "MonoAndroidAssetsPrefix", Path.GetFullPath (Path.Combine (Root, "temp", TestName, "App")) },
-				{ "MonoAndroidResourcePrefix", Path.GetFullPath (Path.Combine (Root, "temp", TestName, "App")) },
-			};
+			using var b = CreateDllBuilder (Path.Combine ("temp", TestName, "Library"));
 			using var appb = CreateApkBuilder (Path.Combine ("temp", TestName, "App"));
 			appb.ThrowOnBuildFailure = false;
-			appb.Save (app);
-			using var b = CreateDllBuilder (Path.Combine ("temp", TestName, "Library"));
 			b.ThrowOnBuildFailure = false;
 			Directory.CreateDirectory (Path.Combine (Root, "temp", TestName, "App"));
+			var envar = new Dictionary<string, string> {
+				{ prefix, Path.Combine (Root, "temp", TestName, "App") },
+			};
 			Assert.IsFalse (b.Build (proj, environmentVariables: envar), "Build should have failed.");
 			Assert.IsTrue (b.LastBuildOutput.ContainsText ("error XA1041"), "XA1041 should have been raised.");
 			Assert.IsFalse (appb.Build (app, environmentVariables: envar), "Build should have failed.");