diff --git a/internal/repository/prune_test.go b/internal/repository/prune_test.go
new file mode 100644
index 000000000..13bf58adc
--- /dev/null
+++ b/internal/repository/prune_test.go
@@ -0,0 +1,93 @@
+package repository_test
+
+import (
+	"context"
+	"math"
+	"testing"
+
+	"github.com/restic/restic/internal/checker"
+	"github.com/restic/restic/internal/repository"
+	"github.com/restic/restic/internal/restic"
+	rtest "github.com/restic/restic/internal/test"
+	"github.com/restic/restic/internal/ui/progress"
+)
+
+func testPrune(t *testing.T, opts repository.PruneOptions, errOnUnused bool) {
+	repo := repository.TestRepository(t).(*repository.Repository)
+	createRandomBlobs(t, repo, 4, 0.5, true)
+	createRandomBlobs(t, repo, 5, 0.5, true)
+	keep, _ := selectBlobs(t, repo, 0.5)
+
+	plan, err := repository.PlanPrune(context.TODO(), opts, repo, func(ctx context.Context, repo restic.Repository) (usedBlobs restic.CountedBlobSet, err error) {
+		return restic.NewCountedBlobSet(keep.List()...), nil
+	}, &progress.NoopPrinter{})
+	rtest.OK(t, err)
+
+	rtest.OK(t, plan.Execute(context.TODO(), &progress.NoopPrinter{}))
+
+	repo = repository.TestOpenBackend(t, repo.Backend()).(*repository.Repository)
+	checker.TestCheckRepo(t, repo, true)
+
+	if errOnUnused {
+		existing := listBlobs(repo)
+		rtest.Assert(t, existing.Equals(keep), "unexpected blobs, wanted %v got %v", keep, existing)
+	}
+}
+
+func TestPrune(t *testing.T) {
+	for _, test := range []struct {
+		name        string
+		opts        repository.PruneOptions
+		errOnUnused bool
+	}{
+		{
+			name: "0",
+			opts: repository.PruneOptions{
+				MaxRepackBytes: math.MaxUint64,
+				MaxUnusedBytes: func(used uint64) (unused uint64) { return 0 },
+			},
+			errOnUnused: true,
+		},
+		{
+			name: "50",
+			opts: repository.PruneOptions{
+				MaxRepackBytes: math.MaxUint64,
+				MaxUnusedBytes: func(used uint64) (unused uint64) { return used / 2 },
+			},
+		},
+		{
+			name: "unlimited",
+			opts: repository.PruneOptions{
+				MaxRepackBytes: math.MaxUint64,
+				MaxUnusedBytes: func(used uint64) (unused uint64) { return math.MaxUint64 },
+			},
+		},
+		{
+			name: "cachableonly",
+			opts: repository.PruneOptions{
+				MaxRepackBytes:     math.MaxUint64,
+				MaxUnusedBytes:     func(used uint64) (unused uint64) { return used / 20 },
+				RepackCachableOnly: true,
+			},
+		},
+		{
+			name: "small",
+			opts: repository.PruneOptions{
+				MaxRepackBytes: math.MaxUint64,
+				MaxUnusedBytes: func(used uint64) (unused uint64) { return math.MaxUint64 },
+				RepackSmall:    true,
+			},
+			errOnUnused: true,
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			testPrune(t, test.opts, test.errOnUnused)
+		})
+		t.Run(test.name+"-recovery", func(t *testing.T) {
+			opts := test.opts
+			opts.UnsafeRecovery = true
+			// unsafeNoSpaceRecovery does not repack partially used pack files
+			testPrune(t, opts, false)
+		})
+	}
+}