diff --git a/src/include/ranges/mrange.cc.h b/src/include/ranges/mrange.cc.h
index 376a61e..447f25b 100644
--- a/src/include/ranges/mrange.cc.h
+++ b/src/include/ranges/mrange.cc.h
@@ -16,6 +16,8 @@ namespace CNORXZ
     {
 	static_assert(sizeof...(Is) == NI,
 		      "sequence size does not match number of indices");
+	CXZ_ASSERT( ( (mRange->sub(Is) != nullptr) and ... ),
+		    "no subranges available" );
 	return std::make_tuple( std::make_shared<Indices>( mRange->sub(Is) )... );
     }
     
@@ -84,27 +86,27 @@ namespace CNORXZ
     template <class... Indices>
     MIndex<Indices...>::MIndex(const MIndex& i) :
 	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>(i.pos()),
+	mRange(rangeCast<RangeType>(i.range())),
 	mIPack(mkIPack(IB::mPos, Isqr<0,NI>{})),
-	mBlockSizes(mkBlockSizes(mIPack,Isqr<0,NI-1>{})),
-	mRange(rangeCast<RangeType>(i.range()))
+	mBlockSizes(mkBlockSizes(mIPack,Isqr<0,NI-1>{}))
     {}
 
     template <class... Indices>
     MIndex<Indices...>& MIndex<Indices...>::operator=(const MIndex& i)
     {
 	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>::operator=(i);
+	mRange = rangeCast<RangeType>(i.range());
 	mIPack = mkIPack(IB::mPos, Isqr<0,NI>{});
 	mBlockSizes = mkBlockSizes(mIPack,Isqr<0,NI-1>{});
-	mRange = rangeCast<RangeType>(i.range());
 	return *this;
     }
 
     template <class... Indices>
     MIndex<Indices...>::MIndex(const RangePtr& range, SizeT pos) :
 	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>(0),
+	mRange(rangeCast<RangeType>(range)),
 	mIPack(mkIPack(IB::mPos, Isqr<0,NI>{})),
-	mBlockSizes(mkBlockSizes(mIPack,Isqr<0,NI-1>{})),
-	mRange(rangeCast<RangeType>(range))
+	mBlockSizes(mkBlockSizes(mIPack,Isqr<0,NI-1>{}))
     {
 	(*this) = pos;
     }
diff --git a/src/include/ranges/mrange.h b/src/include/ranges/mrange.h
index a4a2e80..e8e0c6a 100644
--- a/src/include/ranges/mrange.h
+++ b/src/include/ranges/mrange.h
@@ -82,10 +82,10 @@ namespace CNORXZ
 	template <SizeT I, class Xpr, class F>
 	constexpr decltype(auto) mkIFor(const Xpr& xpr, F&& f) const;
 
+	Sptr<RangeType> mRange;
 	IndexPack mIPack;
 	typedef RemoveRef<decltype(mkBlockSizes(mIPack,Isqr<0,NI-1>{}))> BlockTuple;
 	BlockTuple mBlockSizes;
-	Sptr<RangeType> mRange;
     };
 
     // modified blockSizes; to be used for Slices; can be created from MIndices
diff --git a/src/tests/range_unit_test.cc b/src/tests/range_unit_test.cc
index 2fb7369..2cc9d9e 100644
--- a/src/tests/range_unit_test.cc
+++ b/src/tests/range_unit_test.cc
@@ -1,5 +1,4 @@
 
-
 #include <cstdlib>
 #include <iostream>
 
@@ -114,7 +113,7 @@ namespace
 	}
 
 	SizeT cnt2 = 0;
-	for(auto x: *urx){
+	for(const auto& x: *urx){
 	    EXPECT_EQ(x, mMeta[cnt2++]);
 	}
     }
@@ -130,12 +129,53 @@ namespace
 
 	EXPECT_EQ(mr->size(), mMeta.size()*mSize);
 	EXPECT_EQ(mrx->size(), mMeta.size()*mSize);
+	EXPECT_EQ(mr->dim(), 2u);
 	EXPECT_EQ(mrx->dim(), 2u);
 
-	// further tests!!!
+	EXPECT_TRUE(mrx->begin() != mrx->end());
+	EXPECT_FALSE(mrx->begin() == mrx->end());
+	EXPECT_EQ(mrx->begin().pos(), 0u);
+	EXPECT_EQ(mrx->end().pos(), mrx->size());
+
+	EXPECT_TRUE(mr->begin() != mr->end());
+	EXPECT_FALSE(mr->begin() == mr->end());
+	EXPECT_EQ(mr->begin().pos(), 0u);
+	EXPECT_EQ(mr->end().pos(), mr->size());
+
+	const SizeT mmsize = mMeta.size();
+	auto mkm = [&](SizeT i) { return Tuple<SizeT,String>(i/mmsize,mMeta[i % mmsize]); };
+	
+	SizeT cnt = 0;
+	auto endxi = mr->end();
+	for(auto xi = mr->begin(); xi != endxi; ++xi){
+	    EXPECT_EQ(xi.pos(), cnt);
+	    auto meta = mkm(cnt);
+	    EXPECT_TRUE(*xi == DType(meta));
+	    EXPECT_EQ((*xi).str(), toString(meta));
+	    ++cnt;
+	}
+
+	cnt = 0;
+	auto endxxi = mrx->end();
+	for(auto xxi = mrx->begin(); xxi != endxxi; ++xxi){
+	    EXPECT_EQ(xxi.pos(), cnt);
+	    auto ci = std::get<0>(xxi.pack());
+	    auto ui = std::get<1>(xxi.pack());
+	    Tuple<SizeT,String> meta(*(*ci),*(*ui));
+	    auto meta2 = mkm(cnt);
+	    EXPECT_EQ(meta, meta2);
+	    EXPECT_TRUE(*xxi == meta);
+	    ++cnt;
+	}
+
+	cnt = 0;
+	for(auto x: *mrx){
+	    auto meta = mkm(cnt);
+	    EXPECT_EQ(x, meta);
+	    ++cnt;
+	}
     }
     
-    // UR_Test
     // RCast_Test
 }