gfortran: use test DSL

Formula/gfortran.rb

@@ -94,24 +94,22 @@ class Gfortran < Formula
     # (share/'locale').rmtree
   end
 
-  def test
-    mktemp do
-      fixture = <<-EOS.undent
-        integer,parameter::m=10000
-        real::a(m), b(m)
-        real::fact=0.5
+  test do
+    fixture = <<-EOS.undent
+      integer,parameter::m=10000
+      real::a(m), b(m)
+      real::fact=0.5
 
-        do concurrent (i=1:m)
-          a(i) = a(i) + fact*b(i)
-        end do
-        print *, "done"
-        end
-      EOS
-      Pathname('in.f90').write(fixture)
-      system "#{bin}/gfortran -c in.f90"
-      system "#{bin}/gfortran -o test in.o"
-      `./test`.strip =='done'
-    end
+      do concurrent (i=1:m)
+        a(i) = a(i) + fact*b(i)
+      end do
+      print *, "done"
+      end
+    EOS
+    Pathname('in.f90').write(fixture)
+    system "#{bin}/gfortran -c in.f90"
+    system "#{bin}/gfortran -o test in.o"
+    `./test`.strip =='done'
   end
 
   def caveats; <<-EOS.undent