client: add utilities to encode platforms

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

client/utils_test.go

@@ -0,0 +1,56 @@
+package client
+
+import (
+	"testing"
+
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"gotest.tools/v3/assert"
+)
+
+func TestEncodePlatforms(t *testing.T) {
+	tests := []struct {
+		doc       string
+		platforms []ocispec.Platform
+		expected  []string
+	}{
+		{
+			doc: "single platform",
+			platforms: []ocispec.Platform{
+				{Architecture: "arm64", OS: "windows", Variant: "v8", OSVersion: "99.99.99"},
+			},
+			expected: []string{
+				`{"architecture":"arm64","os":"windows","os.version":"99.99.99","variant":"v8"}`,
+			},
+		},
+		{
+			doc: "multiple platforms",
+			platforms: []ocispec.Platform{
+				{Architecture: "arm64", OS: "linux", Variant: "v8"},
+				{Architecture: "arm64", OS: "windows", Variant: "v8", OSVersion: "99.99.99"},
+			},
+			expected: []string{
+				`{"architecture":"arm64","os":"linux","variant":"v8"}`,
+				`{"architecture":"arm64","os":"windows","os.version":"99.99.99","variant":"v8"}`,
+			},
+		},
+		{
+			doc: "multiple platforms with duplicates",
+			platforms: []ocispec.Platform{
+				{Architecture: "arm64", OS: "linux", Variant: "v8"},
+				{Architecture: "arm64", OS: "windows", Variant: "v8", OSVersion: "99.99.99"},
+				{Architecture: "arm64", OS: "linux", Variant: "v8"},
+			},
+			expected: []string{
+				`{"architecture":"arm64","os":"linux","variant":"v8"}`,
+				`{"architecture":"arm64","os":"windows","os.version":"99.99.99","variant":"v8"}`,
+			},
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.doc, func(t *testing.T) {
+			out, err := encodePlatforms(tc.platforms...)
+			assert.NilError(t, err)
+			assert.DeepEqual(t, out, tc.expected)
+		})
+	}
+}