testing: Add ComposeAggregateTestFunc

This commit adds a function which composes a series of TestFuncs, but
will run all tests before returning an error, unlike ComposeTestFunc.
This is useful when verifying contents of state in acceptance tests and
it is desirable to see all the failing cases in one run for slow
resources.

helper/resource/testing.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/davecgh/go-spew/spew"
 	"github.com/hashicorp/go-getter"
+	"github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/terraform/config/module"
 	"github.com/hashicorp/terraform/helper/logging"
 	"github.com/hashicorp/terraform/terraform"
@@ -520,6 +521,28 @@ func ComposeTestCheckFunc(fs ...TestCheckFunc) TestCheckFunc {
 	}
 }
 
+// ComposeAggregateTestCheckFunc lets you compose multiple TestCheckFuncs into
+// a single TestCheckFunc.
+//
+// As a user testing their provider, this lets you decompose your checks
+// into smaller pieces more easily.
+//
+// Unlike ComposeTestCheckFunc, ComposeAggergateTestCheckFunc runs _all_ of the
+// TestCheckFuncs and aggregates failures.
+func ComposeAggregateTestCheckFunc(fs ...TestCheckFunc) TestCheckFunc {
+	return func(s *terraform.State) error {
+		var result *multierror.Error
+
+		for i, f := range fs {
+			if err := f(s); err != nil {
+				result = multierror.Append(result, fmt.Errorf("Check %d/%d error: %s", i+1, len(fs), err))
+			}
+		}
+
+		return result.ErrorOrNil()
+	}
+}
+
 // TestCheckResourceAttrSet is a TestCheckFunc which ensures a value
 // exists in state for the given name/key combination. It is useful when
 // testing that computed values were set, when it is not possible to

helper/resource/testing_test.go

@@ -1,11 +1,14 @@
 package resource
 
 import (
+	"errors"
 	"fmt"
 	"os"
+	"strings"
 	"sync/atomic"
 	"testing"
 
+	"github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/terraform/terraform"
 )
 
@@ -352,6 +355,30 @@ func TestTest_stepError(t *testing.T) {
 	}
 }
 
+func TestComposeAggregateTestCheckFunc(t *testing.T) {
+	check1 := func(s *terraform.State) error {
+		return errors.New("Error 1")
+	}
+
+	check2 := func(s *terraform.State) error {
+		return errors.New("Error 2")
+	}
+
+	f := ComposeAggregateTestCheckFunc(check1, check2)
+	err := f(nil)
+	if err == nil {
+		t.Fatalf("Expected errors")
+	}
+
+	multi := err.(*multierror.Error)
+	if !strings.Contains(multi.Errors[0].Error(), "Error 1") {
+		t.Fatalf("Expected Error 1, Got %s", multi.Errors[0])
+	}
+	if !strings.Contains(multi.Errors[1].Error(), "Error 2") {
+		t.Fatalf("Expected Error 2, Got %s", multi.Errors[1])
+	}
+}
+
 func TestComposeTestCheckFunc(t *testing.T) {
 	cases := []struct {
 		F      []TestCheckFunc