Rebuild PyCall after installing ipython

Author: tkf

test/install_dependencies.jl

@@ -12,16 +12,20 @@ Pkg.build("PyCall")
 using Compat: @info
 using IPython
 
-if VERSION >= v"0.7.0-"
-    @info "PyCall/deps/build.log:"
-    print(read(
-        joinpath(dirname(dirname(pathof(IPython.PyCall))), "deps", "build.log"),
-        String))
-end
-
 IPython.install_dependency("pytest"; force=true)
 IPython.install_dependency("ipython"; force=true)
 if get(ENV, "CONDA_JL_VERSION", "") == "2"
     # For IPython.testing.globalipapp
     IPython.install_dependency("mock"; force=true)
 end
+
+# Build PyCall again, since above installation could have changed
+# Python versions.
+Pkg.build("PyCall")
+
+if VERSION >= v"0.7.0-"
+    @info "PyCall/deps/build.log:"
+    print(read(
+        joinpath(dirname(dirname(pathof(IPython.PyCall))), "deps", "build.log"),
+        String))
+end

test/runtests.jl

@@ -1,7 +1,22 @@
 # module TestIPython
 
 if lowercase(get(ENV, "CI", "false")) == "true"
-    include("install_dependencies.jl")
+    let
+        if VERSION < v"0.7.0-"
+            setup_code = ""
+        else
+            setup_code = Base.load_path_setup_code()
+        end
+        path = joinpath(@__DIR__, "install_dependencies.jl")
+        code = """
+        $setup_code
+        include("$(escape_string(path))")
+        """
+        run(`$(Base.julia_cmd()) -e $code`)
+        # Run install_dependencies.jl in a separate process since it
+        # may re-build PyCall.  In that case, we need to load
+        # re-precompiled PyCall and IPython.
+    end
 end
 
 include("preamble.jl")