[c++/m] Add Source referringTags method

Adds the referringTags method to the Source
entity on c++ and matlab side and introduces a
corresponding test.

Author: mpsonntag

+nix/Source.m

@@ -58,5 +58,10 @@
             retObj = nix.Utils.fetchObjList('Source::referringDataArrays', ...
                 obj.nix_handle, @nix.DataArray);
         end
+
+        function retObj = referring_tags(obj)
+            retObj = nix.Utils.fetchObjList('Source::referringTags', ...
+                obj.nix_handle, @nix.Tag);
+        end
     end;
 end

nix_mx.cc

@@ -245,7 +245,8 @@ void mexFunction(int            nlhs,
             .reg("setNoneDefinition", SETTER(const boost::none_t, nix::Source, definition))
             .reg("parentSource", GETTER(nix::Source, nix::Source, parentSource))
             .reg("sourceCount", GETTER(nix::ndsize_t, nix::Source, sourceCount))
-            .reg("referringDataArrays", GETTER(std::vector<nix::DataArray>, nix::Source, referringDataArrays));
+            .reg("referringDataArrays", GETTER(std::vector<nix::DataArray>, nix::Source, referringDataArrays))
+            .reg("referringTags", GETTER(std::vector<nix::Tag>, nix::Source, referringTags));
 
         classdef<nix::Tag>("Tag", methods)
             .desc(&nixtag::describe)

tests/TestSource.m

@@ -22,6 +22,7 @@
     funcs{end+1} = @test_set_metadata;
     funcs{end+1} = @test_open_metadata;
     funcs{end+1} = @test_referring_data_arrays;
+    funcs{end+1} = @test_referring_tags;
 end
 
 %% Test: fetch sources
@@ -226,3 +227,22 @@
     d2.add_source(s);
     assert(size(s.referring_data_arrays, 1) == 2);
 end
+
+%% Test: Referring tags
+function [] = test_referring_tags( varargin )
+    fileName = fullfile(pwd, 'tests', 'testRW.h5');
+    f = nix.File(fileName, nix.FileMode.Overwrite);
+    b = f.create_block('testBlock', 'nixBlock');
+    s = b.create_source('testSource', 'nixSource');
+
+    assert(isempty(s.referring_tags));
+
+    t1 = b.create_tag('testTag1', 'nixTag', [1, 2]);
+    t1.add_source(s);
+    assert(~isempty(s.referring_tags));
+    assert(strcmp(s.referring_tags{1}.name, t1.name));
+
+    t2 = b.create_tag('testTag2', 'nixTag', [1, 2]);
+    t2.add_source(s);
+    assert(size(s.referring_tags, 1) == 2);
+end