diff --git a/src/ca_roots.jl b/src/ca_roots.jl
index e39e173..b67d2c9 100644
--- a/src/ca_roots.jl
+++ b/src/ca_roots.jl
@@ -111,8 +111,8 @@ end
 
 const CA_ROOTS_VARS = [
     "JULIA_SSL_CA_ROOTS_PATH"
-    "SSL_CERT_DIR"
     "SSL_CERT_FILE"
+    "SSL_CERT_DIR"
 ]
 
 function _ca_roots(allow_nothing::Bool)
diff --git a/test/runtests.jl b/test/runtests.jl
index 14a1674..3aed8a9 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -17,6 +17,7 @@ include("setup.jl")
     @testset "env vars" begin
         unset = ca_roots(), ca_roots_path()
         value = "Why hello!"
+        # set only one CA_ROOT_VAR
         for var in CA_ROOTS_VARS
             ENV[var] = value
             @test ca_roots() == value
@@ -26,12 +27,14 @@ include("setup.jl")
             @test ca_roots_path() == unset[2]
             clear_env()
         end
-        for (i, var) in enumerate(CA_ROOTS_VARS)
-            ENV[var] = string(i)
-        end
-        @test ca_roots() == "1"
-        @test ca_roots_path() == "1"
-        ENV[CA_ROOTS_VARS[1]] = ""
+        # set multiple CA_ROOT_VARS with increasing precedence
+        ENV["SSL_CERT_DIR"] = "3"
+        @test ca_roots() == ca_roots_path() == "3"
+        ENV["SSL_CERT_FILE"] = "2"
+        @test ca_roots() == ca_roots_path() == "2"
+        ENV["JULIA_SSL_CA_ROOTS_PATH"] = "1"
+        @test ca_roots() == ca_roots_path() == "1"
+        ENV["JULIA_SSL_CA_ROOTS_PATH"] = ""
         @test ca_roots() == unset[1]
         @test ca_roots_path() == unset[2]
         clear_env()