hcp-sbom: add prepare tests for the provisioner

provisioner/hcp-sbom/provisioner_test.go

@@ -0,0 +1,86 @@
+package hcp_sbom
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+	"github.com/hashicorp/packer-plugin-sdk/template/interpolate"
+)
+
+func TestConfigPrepare(t *testing.T) {
+	tests := []struct {
+		name               string
+		inputConfig        map[string]interface{}
+		interpolateContext interpolate.Context
+		expectConfig       *Config
+		expectError        bool
+	}{
+		{
+			"empty config, should error without a source",
+			map[string]interface{}{},
+			interpolate.Context{},
+			nil,
+			true,
+		},
+		{
+			"config with full context for interpolation: success",
+			map[string]interface{}{
+				"source": "{{ .Name }}",
+			},
+			interpolate.Context{
+				Data: &struct {
+					Name string
+				}{
+					Name: "testInterpolate",
+				},
+			},
+			&Config{
+				Source: "testInterpolate",
+			},
+			false,
+		},
+		{
+			// Note: this will look weird to reviewers, but is actually
+			// expected for the moment.
+			// Refer to the comment in `Prepare` for context as to WHY
+			// this cannot be considered an error.
+			"config with sbom name as interpolated value, without it in context, replace with a placeholder",
+			map[string]interface{}{
+				"source":    "test",
+				"sbom_name": "{{ .Name }}",
+			},
+			interpolate.Context{},
+			&Config{
+				Source:   "test",
+				SbomName: "<no value>",
+			},
+			false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			prov := &Provisioner{}
+			prov.config.ctx = tt.interpolateContext
+			err := prov.Prepare(tt.inputConfig)
+			if err != nil && !tt.expectError {
+				t.Fatalf("configuration unexpectedly failed to prepare: %s", err)
+			}
+
+			if err == nil && tt.expectError {
+				t.Fatalf("configuration succeeded to prepare, but should have failed")
+			}
+
+			if err != nil {
+				t.Logf("config had error %q", err)
+				return
+			}
+
+			diff := cmp.Diff(prov.config, *tt.expectConfig, cmpopts.IgnoreUnexported(Config{}))
+			if diff != "" {
+				t.Errorf("configuration returned by `Prepare` is different from what was expected: %s", diff)
+			}
+		})
+	}
+}