rebuild PyCall when in CI

Author: Christopher Doris

test/runtests.jl

@@ -1,3 +1,12 @@
+if get(ENV, "CI", "") != ""
+    # In CI we need to rebuild PyCall otherwise it fails a precompilation trying to use
+    # an interpreter that doesn't exist, presumably as a result of cacheing between CI
+    # runs.
+    using Pkg
+    ENV["PYTHON"] = Sys.which("python")
+    Pkg.build("PyCall")
+end
+
 using TestItemRunner
 
 @run_package_tests
@@ -6,7 +15,7 @@ using TestItemRunner
     using PythonCall: PythonCall
     using Pkg: Pkg
     ENV["PYTHON"] = PythonCall.python_executable_path()
-    @info "Building PyCall..." ENV["PYTHON"]
+    @info "Building PyCall" python = ENV["PYTHON"]
     Pkg.build("PyCall")
     using PyCall
 end