fix few failing tests with a fresh seed, and duplicate guardsrand's l…

…ogic

guardsrand can't be used directly, as then the testset's body is wrapped
in a function, which causes problem with overwriting loop variable ("outer"),
using `using`, defining new methods, etc.

stdlib/Test/src/Test.jl

@@ -941,23 +941,28 @@ function testset_beginend(args, tests, source)
     # finally removing the testset and giving it a chance to take
     # action (such as reporting the results)
     quote
-        # GLOBAL_RNG is re-seeded with its own seed to ease reproduce a failed test
-        guardsrand(Base.GLOBAL_RNG.seed) do
-            ts = $(testsettype)($desc; $options...)
-            # this empty loop is here to force the block to be compiled,
-            # which is needed for backtrace scrubbing to work correctly.
-            while false; end
-            push_testset(ts)
-            try
-                $(esc(tests))
-            catch err
-                # something in the test block threw an error. Count that as an
-                # error in this test set
-                record(ts, Error(:nontest_error, :(), err, catch_backtrace(), $(QuoteNode(source))))
-            end
-            pop_testset()
-            finish(ts)
+        ts = $(testsettype)($desc; $options...)
+        # this empty loop is here to force the block to be compiled,
+        # which is needed for backtrace scrubbing to work correctly.
+        while false; end
+        push_testset(ts)
+        # we reproduce the logic of guardsrand, but this function
+        # cannot be used as it changes slightly the semantic of @testset,
+        # by wrapping the body in a function
+        oldrng = copy(Base.GLOBAL_RNG)
+        try
+            # GLOBAL_RNG is re-seeded with its own seed to ease reproduce a failed test
+            srand(Base.GLOBAL_RNG.seed)
+            $(esc(tests))
+        catch err
+            # something in the test block threw an error. Count that as an
+            # error in this test set
+            record(ts, Error(:nontest_error, :(), err, catch_backtrace(), $(QuoteNode(source))))
+        finally
+            copy!(Base.GLOBAL_RNG, oldrng)
         end
+        pop_testset()
+        finish(ts)
     end
 end
 
@@ -1001,23 +1006,25 @@ function testset_forloop(args, testloop, source)
     # wrapped in the outer loop provided by the user
     tests = testloop.args[2]
     blk = quote
-        guardsrand(Base.GLOBAL_RNG.seed) do
-            # Trick to handle `break` and `continue` in the test code before
-            # they can be handled properly by `finally` lowering.
-            if !first_iteration
-                pop_testset()
-                push!(arr, finish(ts))
-            end
-            ts = $(testsettype)($desc; $options...)
-            push_testset(ts)
-            first_iteration = false
-            try
-                $(esc(tests))
-            catch err
-                # Something in the test block threw an error. Count that as an
-                # error in this test set
-                record(ts, Error(:nontest_error, :(), err, catch_backtrace(), $(QuoteNode(source))))
-            end
+        # Trick to handle `break` and `continue` in the test code before
+        # they can be handled properly by `finally` lowering.
+        if !first_iteration
+            pop_testset()
+            push!(arr, finish(ts))
+        end
+        ts = $(testsettype)($desc; $options...)
+        push_testset(ts)
+        first_iteration = false
+        oldrng = copy(Base.GLOBAL_RNG)
+        try
+            srand(Base.GLOBAL_RNG.seed)
+            $(esc(tests))
+        catch err
+            # Something in the test block threw an error. Count that as an
+            # error in this test set
+            record(ts, Error(:nontest_error, :(), err, catch_backtrace(), $(QuoteNode(source))))
+        finally
+            copy!(Base.GLOBAL_RNG, oldrng)
         end
     end
     quote

stdlib/Test/test/runtests.jl

@@ -286,7 +286,7 @@ end
             end
             @testset "some loops fail" begin
                 @testset for i in 1:5
-                    @test i <= rand(1:3)
+                    @test i <= 4
                 end
                 # should add 3 errors and 3 passing tests
                 @testset for i in 1:6
@@ -651,7 +651,8 @@ end
      rm(f; force=true)
  end
 
-@testset "@testset is wrapped in a `guardsrand` block" begin
+@testset "@testset preserves GLOBAL_RNG's state, and re-seeds it" begin
+    # i.e. it behaves as if it was wrapped in a `guardsrand(GLOBAL_RNG.seed)` block
     seed = rand(UInt128)
     srand(seed)
     a = rand()

test/linalg/arnoldi.jl

@@ -95,6 +95,7 @@ using Test
     end
 
     @testset "Symmetric generalized with singular B" begin
+        srand(123)
         n = 10
         k = 3
         A = randn(n,n); A = A'A

test/linalg/lu.jl

@@ -183,6 +183,7 @@ dimg  = randn(n)/2
 end
 
 @testset "conversion" begin
+    srand(3)
     a = Tridiagonal(rand(9),rand(10),rand(9))
     fa = Array(a)
     falu = lufact(fa)

test/sparse/sparse.jl

@@ -426,8 +426,7 @@ end
         @test_throws ArgumentError permute!(A, p, (r = copy(q); r[2] = n + 1; r))
     end
     @testset "overall functionality of [c]transpose[!] and permute[!]" begin
-        for (_m, _n) in ((smalldim, smalldim), (smalldim, largedim), (largedim, smalldim))
-            m, n = _m, _n # to avoid overwriting variables from above in the for loop
+        for (m, n) in ((smalldim, smalldim), (smalldim, largedim), (largedim, smalldim))
             A = sprand(m, n, nzprob)
             At = transpose(A)
             # transpose[!]