add some show testing

Author: Jutho

test/tensors/tensors.jl

@@ -624,3 +624,52 @@ end
         end
     end
 end
+
+@timedtestset "show tensors" begin
+    for V in (ℂ^2, Z2Space(0 => 2, 1 => 2), SU2Space(0 => 2, 1 => 2))
+        t1 = ones(Float32, V ⊗ V, V)
+        t2 = randn(ComplexF64, V ⊗ V ⊗ V)
+        # test unlimited output
+        for t in (t1, t2, t1', t2')
+            output = IOBuffer()
+            summary(output, t)
+            print(output, ":\n codomain: ")
+            show(output, MIME("text/plain"), codomain(t))
+            print(output, "\n domain: ")
+            show(output, MIME("text/plain"), domain(t))
+            print(output, "\n blocks: \n")
+            first = true
+            for (c, b) in blocks(t)
+                first || print(output, "\n\n")
+                print(output, " * ")
+                show(output, MIME("text/plain"), c)
+                print(output, " => ")
+                show(output, MIME("text/plain"), b)
+                first = false
+            end
+            outputstr = String(take!(output))
+            @test outputstr == sprint(show, MIME("text/plain"), t)
+        end
+
+        # test limited output with a single block
+        t = randn(Float64, V ⊗ V, V)' # we know there is a single space in the codomain, so that blocks have 2 rows
+        output = IOBuffer()
+        summary(output, t)
+        print(output, ":\n codomain: ")
+        show(output, MIME("text/plain"), codomain(t))
+        print(output, "\n domain: ")
+        show(output, MIME("text/plain"), domain(t))
+        print(output, "\n blocks: \n")
+        c = unit(sectortype(t))
+        b = block(t, c)
+        print(output, " * ")
+        show(output, MIME("text/plain"), c)
+        print(output, " => ")
+        show(output, MIME("text/plain"), b)
+        if length(blocks(t)) > 1
+            print(output, "\n\n *   …   [output of 1 more block(s) truncated]")
+        end
+        outputstr = String(take!(output))
+        @test outputstr == sprint(show, MIME("text/plain"), t; context = (:limit => true, :displaysize => (12, 100)))
+    end
+end