test: assert service interpolation behavior

Ported from pre-0.9 tests.

client/allocrunner/taskrunner/service_hook_test.go

@@ -0,0 +1,86 @@
+package taskrunner
+
+import (
+	"testing"
+
+	"github.com/hashicorp/nomad/client/taskenv"
+	"github.com/hashicorp/nomad/nomad/structs"
+	"github.com/stretchr/testify/require"
+)
+
+// TestTaskRunner_ServiceHook_InterpolateServices asserts that all service
+// and check fields are properly interpolated.
+func TestTaskRunner_ServiceHook_InterpolateServices(t *testing.T) {
+	t.Parallel()
+	services := []*structs.Service{
+		{
+			Name:      "${name}",
+			PortLabel: "${portlabel}",
+			Tags:      []string{"${tags}"},
+			Checks: []*structs.ServiceCheck{
+				{
+					Name:          "${checkname}",
+					Type:          "${checktype}",
+					Command:       "${checkcmd}",
+					Args:          []string{"${checkarg}"},
+					Path:          "${checkstr}",
+					Protocol:      "${checkproto}",
+					PortLabel:     "${checklabel}",
+					InitialStatus: "${checkstatus}",
+					Method:        "${checkmethod}",
+					Header: map[string][]string{
+						"${checkheaderk}": {"${checkheaderv}"},
+					},
+				},
+			},
+		},
+	}
+
+	env := &taskenv.TaskEnv{
+		EnvMap: map[string]string{
+			"name":         "name",
+			"portlabel":    "portlabel",
+			"tags":         "tags",
+			"checkname":    "checkname",
+			"checktype":    "checktype",
+			"checkcmd":     "checkcmd",
+			"checkarg":     "checkarg",
+			"checkstr":     "checkstr",
+			"checkpath":    "checkpath",
+			"checkproto":   "checkproto",
+			"checklabel":   "checklabel",
+			"checkstatus":  "checkstatus",
+			"checkmethod":  "checkmethod",
+			"checkheaderk": "checkheaderk",
+			"checkheaderv": "checkheaderv",
+		},
+	}
+
+	interpolated := interpolateServices(env, services)
+
+	exp := []*structs.Service{
+		{
+			Name:      "name",
+			PortLabel: "portlabel",
+			Tags:      []string{"tags"},
+			Checks: []*structs.ServiceCheck{
+				{
+					Name:          "checkname",
+					Type:          "checktype",
+					Command:       "checkcmd",
+					Args:          []string{"checkarg"},
+					Path:          "checkstr",
+					Protocol:      "checkproto",
+					PortLabel:     "checklabel",
+					InitialStatus: "checkstatus",
+					Method:        "checkmethod",
+					Header: map[string][]string{
+						"checkheaderk": {"checkheaderv"},
+					},
+				},
+			},
+		},
+	}
+
+	require.Equal(t, exp, interpolated)
+}