gnu: Add dune-uggrid.

* gnu/packages/maths.scm (dune-uggrid): New variable.
(dune-grid)[propagated-inputs]: Add dune-uggrid dependency, so
that the UGGrid class in dune-grid can be used by packages that
have dune-grid as input.
(dune-functions)[arguments]: Enable tests that previously weren't
built as they require dune-uggrid.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/maths.scm

@@ -4656,6 +4656,42 @@ This package contains the basic DUNE geometry classes.")
     ;; GPL version 2 with "runtime exception"
     (license license:gpl2)))
 
+(define-public dune-uggrid
+  (package
+    (name "dune-uggrid")
+    (version "2.6.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "https://dune-project.org/download/"
+                           version "/dune-uggrid-" version ".tar.gz"))
+       (sha256
+        (base32
+         "05l7a1gb78mny49anyxk6rjvn66rhgm30y72v5cjg0m5kfgr1a1f"))))
+    (build-system cmake-build-system)
+    (arguments
+     `(#:phases
+       (modify-phases %standard-phases
+         (add-after 'build 'build-tests
+           (lambda* (#:key make-flags #:allow-other-keys)
+             (apply invoke "make" "build_tests" make-flags))))))
+    (inputs
+     `(("dune-common" ,dune-common)
+       ("openmpi" ,openmpi)))
+    (native-inputs
+     `(("gfortran" ,gfortran)
+       ("pkg-config" ,pkg-config)))
+    (home-page "https://dune-project.org/")
+    (synopsis "Distributed and Unified Numerics Environment")
+    (description "DUNE, the Distributed and Unified Numerics Environment is a
+modular toolbox for solving @dfn{partial differential equations} (PDEs) with
+grid-based methods.  It supports the easy implementation of methods like
+@dfn{Finite Elements} (FE), @dfn{Finite Volumes} (FV), and also @dfn{Finite
+Differences} (FD).
+
+This package contains the DUNE UG grid classes.")
+    (license license:lgpl2.1)))
+
 (define-public dune-grid
   (package
     (name "dune-grid")
@@ -4685,6 +4721,8 @@ This package contains the basic DUNE geometry classes.")
        ("openblas" ,openblas)
        ("openmpi" ,openmpi)
        ("python" ,python)))
+    (propagated-inputs
+     `(("dune-uggrid" ,dune-uggrid)))
     (native-inputs
      `(("gfortran" ,gfortran)
        ("pkg-config" ,pkg-config)))
@@ -4898,7 +4936,20 @@ operating on statically typed trees of objects.")
         (base32
          "1an8gb477n8j0kzpbrv7nr1snh8pxip0gsxq6w63jc83gg3dj200"))))
     (build-system cmake-build-system)
-    (arguments `(#:tests? #f)) ; FIXME: tests require dune-uugrid
+    (arguments
+     `(#:phases
+       (modify-phases %standard-phases
+         (add-after 'unpack 'disable-failing-tests
+           (lambda _
+             (setenv "ARGS"
+                     ;; unable to load GMSH file in this test
+                     "--exclude-regex gridviewfunctionspacebasistest")
+            #t))
+         (add-after 'build 'build-tests
+           (lambda* (#:key make-flags #:allow-other-keys)
+             (apply invoke "make" "build_tests" make-flags)))
+         (add-before 'check 'mpi-setup
+           ,%openmpi-setup))))
     (inputs
      `(("dune-common" ,dune-common)
        ("dune-istl" ,dune-istl)