diff --git a/agent/config/builder.go b/agent/config/builder.go
index 9f7c0e005..73c067811 100644
--- a/agent/config/builder.go
+++ b/agent/config/builder.go
@@ -174,6 +174,9 @@ func (b *Builder) ReadPath(path string) error {
 // ReadFile parses a JSON or HCL config file and appends it to the list of
 // config sources.
 func (b *Builder) ReadFile(path string) error {
+	if !strings.HasSuffix(path, ".json") && !strings.HasSuffix(path, ".hcl") {
+		return fmt.Errorf(`Missing or invalid file extension for %q. Please use ".json" or ".hcl".`, path)
+	}
 	data, err := ioutil.ReadFile(path)
 	if err != nil {
 		return fmt.Errorf("config: ReadFile failed on %s: %s", path, err)
diff --git a/api/agent_test.go b/api/agent_test.go
index 92b7b5c32..e5eecb11c 100644
--- a/api/agent_test.go
+++ b/api/agent_test.go
@@ -7,6 +7,9 @@ import (
 	"testing"
 	"time"
 
+	"os"
+	"path/filepath"
+
 	"github.com/hashicorp/consul/testutil"
 	"github.com/hashicorp/serf/serf"
 )
@@ -57,11 +60,14 @@ func TestAPI_AgentReload(t *testing.T) {
 	t.Parallel()
 
 	// Create our initial empty config file, to be overwritten later
-	configFile := testutil.TempFile(t, "reload")
-	if _, err := configFile.Write([]byte("{}")); err != nil {
-		t.Fatalf("err: %s", err)
+	cfgDir := testutil.TempDir(t, "consul-config")
+	defer os.RemoveAll(cfgDir)
+
+	cfgFilePath := filepath.Join(cfgDir, "reload.json")
+	configFile, err := os.Create(cfgFilePath)
+	if err != nil {
+		t.Fatalf("Unable to create file %v, got error:%v", cfgFilePath, err)
 	}
-	configFile.Close()
 
 	c, s := makeClientWithConfig(t, nil, func(conf *testutil.TestServerConfig) {
 		conf.Args = []string{"-config-file", configFile.Name()}
@@ -72,7 +78,7 @@ func TestAPI_AgentReload(t *testing.T) {
 
 	// Update the config file with a service definition
 	config := `{"service":{"name":"redis", "port":1234}}`
-	err := ioutil.WriteFile(configFile.Name(), []byte(config), 0644)
+	err = ioutil.WriteFile(configFile.Name(), []byte(config), 0644)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
diff --git a/command/agent_test.go b/command/agent_test.go
index 431fff7e6..2ab73e35e 100644
--- a/command/agent_test.go
+++ b/command/agent_test.go
@@ -229,11 +229,17 @@ func TestProtectDataDir(t *testing.T) {
 		t.Fatalf("err: %v", err)
 	}
 
-	cfgFile := testutil.TempFile(t, "consul")
-	defer os.Remove(cfgFile.Name())
+	cfgDir := testutil.TempDir(t, "consul-config")
+	defer os.RemoveAll(cfgDir)
+
+	cfgFilePath := filepath.Join(cfgDir, "consul.json")
+	cfgFile, err := os.Create(cfgFilePath)
+	if err != nil {
+		t.Fatalf("Unable to create file %v, got error:%v", cfgFilePath, err)
+	}
 
 	content := fmt.Sprintf(`{"server": true, "bind_addr" : "10.0.0.1", "data_dir": "%s"}`, dir)
-	_, err := cfgFile.Write([]byte(content))
+	_, err = cfgFile.Write([]byte(content))
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}