Add target test coverage

[l3ender]

Resolves #75.

[l3ender]

Reran Styker on these changes and there's only one item left in addTarget:

diff --git a/lib/pbxProject.js b/lib/pbxProject.js
index 3097678..d3d05bd 100644
--- a/lib/pbxProject.js
+++ b/lib/pbxProject.js
@@ -1440,7 +1440,7 @@ pbxProject.prototype.addTarget = function(name, type, subfolder) {
     var productName = targetName,
         productType = producttypeForTargettype(targetType),
         productFileType = filetypeForProducttype(productType),
-        productFile = this.addProductFile(productName, { group: 'Copy Files', 'target': targetUuid, 'explicitFileType': productFileType}),
+        productFile = this.addProductFile(productName, { group: '', '': targetUuid, 'explicitFileType': productFileType}),
         productFileName = productFile.basename;

However, from what I can tell, the group and target options aren't used at all in this code path. I'm leaving them alone, but I think the PR is ready given that the method is well-covered now.

A nice side benefit of these changes is that pbxProject.js now has a mutation score in the green (>80%)!

@brodybits

[brodybits]

Merging now, thank you!

Your statement about the remaining mutations sounds right. It would be nice if we could take a better look, with maybe some more testing, to see if we can just remove these someday.

Nice to hear that you got the greener score, I will regenerate my report now.