sweep: add new interface Cluster to manage grouping inputs

This commit adds a new interface `Cluster` to manage cluster-level
inputs grouping. This new interface replaces the `inputCluster` and will
be futher refactored so the sweeper can use a much smaller coin
selection lock.

sweep/sweeper_test.go

@@ -1882,115 +1882,6 @@ func TestSweeperShutdownHandling(t *testing.T) {
 	require.Error(t, err)
 }
 
-// TestGetInputLists checks that the expected input sets are returned based on
-// whether there are retried inputs or not.
-func TestGetInputLists(t *testing.T) {
-	t.Parallel()
-
-	// Create a test param with a dummy fee preference. This is needed so
-	// `feeRateForPreference` won't throw an error.
-	param := Params{Fee: FeeEstimateInfo{ConfTarget: 1}}
-
-	// Create a mock input and mock all the methods used in this test.
-	testInput := &input.MockInput{}
-	testInput.On("RequiredLockTime").Return(0, false)
-	testInput.On("WitnessType").Return(input.CommitmentAnchor)
-	testInput.On("OutPoint").Return(&wire.OutPoint{Index: 1})
-	testInput.On("RequiredTxOut").Return(nil)
-	testInput.On("UnconfParent").Return(nil)
-	testInput.On("SignDesc").Return(&input.SignDescriptor{
-		Output: &wire.TxOut{Value: 100_000},
-	})
-
-	// Create a new and a retried input.
-	//
-	// NOTE: we use the same input.Input for both pending inputs as we only
-	// test the logic of returning the correct non-nil input sets, and not
-	// the content the of sets. To validate the content of the sets, we
-	// should test `generateInputPartitionings` instead.
-	newInput := &pendingInput{
-		Input:  testInput,
-		params: param,
-	}
-	oldInput := &pendingInput{
-		Input:           testInput,
-		params:          param,
-		publishAttempts: 1,
-	}
-
-	// clusterNew contains only new inputs.
-	clusterNew := pendingInputs{
-		wire.OutPoint{Index: 1}: newInput,
-	}
-
-	// clusterMixed contains a mixed of new and retried inputs.
-	clusterMixed := pendingInputs{
-		wire.OutPoint{Index: 1}: newInput,
-		wire.OutPoint{Index: 2}: oldInput,
-	}
-
-	// clusterOld contains only retried inputs.
-	clusterOld := pendingInputs{
-		wire.OutPoint{Index: 2}: oldInput,
-	}
-
-	// Create a test sweeper.
-	s := New(&UtxoSweeperConfig{
-		MaxInputsPerTx: DefaultMaxInputsPerTx,
-	})
-
-	testCases := []struct {
-		name              string
-		cluster           inputCluster
-		expectedNilAllSet bool
-		expectNilNewSet   bool
-	}{
-		{
-			// When there are only new inputs, we'd expect the
-			// first returned set(allSets) to be empty.
-			name:              "new inputs only",
-			cluster:           inputCluster{inputs: clusterNew},
-			expectedNilAllSet: true,
-			expectNilNewSet:   false,
-		},
-		{
-			// When there are only retried inputs, we'd expect the
-			// second returned set(newSet) to be empty.
-			name:              "retried inputs only",
-			cluster:           inputCluster{inputs: clusterOld},
-			expectedNilAllSet: false,
-			expectNilNewSet:   true,
-		},
-		{
-			// When there are mixed inputs, we'd expect two sets
-			// are returned.
-			name:              "mixed inputs",
-			cluster:           inputCluster{inputs: clusterMixed},
-			expectedNilAllSet: false,
-			expectNilNewSet:   false,
-		},
-	}
-
-	for _, tc := range testCases {
-		tc := tc
-
-		t.Run(tc.name, func(t *testing.T) {
-			t.Parallel()
-
-			allSets, newSets, err := s.getInputLists(tc.cluster)
-			require.NoError(t, err)
-
-			if tc.expectNilNewSet {
-				require.Nil(t, newSets)
-			}
-
-			if tc.expectedNilAllSet {
-				require.Nil(t, allSets)
-			}
-		})
-	}
-}
-
 // TestMarkInputsPendingPublish checks that given a list of inputs with
 // different states, only the non-terminal state will be marked as `Published`.
 func TestMarkInputsPendingPublish(t *testing.T) {