validate get step names, not resources; add test

validate.go

@@ -222,12 +222,12 @@ func validateJobs(c Config) ([]Warning, error) {
 
 		encountered := map[string]int{}
 		for _, input := range job.Inputs() {
-			encountered[input.ResourceName()]++
+			encountered[input.Get]++
 
-			if encountered[input.ResourceName()] == 2 {
+			if encountered[input.Get] == 2 {
 				errorMessages = append(
 					errorMessages,
-					identifier+fmt.Sprintf(" has get steps with the same name: %s", input.ResourceName()),
+					fmt.Sprintf("%s has get steps with the same name: %s", identifier, input.Get),
 				)
 			}
 		}

validate_test.go

@@ -1,9 +1,10 @@
 package atc_test
 
 import (
-	. "github.com/concourse/atc"
 	"strings"
 
+	. "github.com/concourse/atc"
+
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 )
@@ -443,6 +444,46 @@ var _ = Describe("ValidateConfig", func() {
 			})
 		})
 
+		Context("when a job has duplicate inputs with different resources", func() {
+			BeforeEach(func() {
+				job.Plan = append(job.Plan, PlanConfig{
+					Get:      "some-resource",
+					Resource: "a",
+				})
+				job.Plan = append(job.Plan, PlanConfig{
+					Get:      "some-resource",
+					Resource: "b",
+				})
+
+				config.Jobs = append(config.Jobs, job)
+			})
+
+			It("returns a single error", func() {
+				Expect(errorMessages).To(HaveLen(1))
+				Expect(errorMessages[0]).To(ContainSubstring("invalid jobs:"))
+				Expect(strings.Count(errorMessages[0], "has get steps with the same name: some-resource")).To(Equal(1))
+			})
+		})
+
+		Context("when a job gets the same resource multiple times but with different names", func() {
+			BeforeEach(func() {
+				job.Plan = append(job.Plan, PlanConfig{
+					Get:      "a",
+					Resource: "some-resource",
+				})
+				job.Plan = append(job.Plan, PlanConfig{
+					Get:      "b",
+					Resource: "some-resource",
+				})
+
+				config.Jobs = append(config.Jobs, job)
+			})
+
+			It("returns no errors", func() {
+				Expect(errorMessages).To(HaveLen(0))
+			})
+		})
+
 		Context("when a job has duplicate inputs via aggregate", func() {
 			BeforeEach(func() {
 				job.Plan = append(job.Plan, PlanConfig{