diff --git a/specs/phase0/beacon-chain.md b/specs/phase0/beacon-chain.md
index f40f0096b..95f06f125 100644
--- a/specs/phase0/beacon-chain.md
+++ b/specs/phase0/beacon-chain.md
@@ -110,6 +110,10 @@
     - [Helper functions](#helper-functions-1)
     - [Justification and finalization](#justification-and-finalization)
     - [Rewards and penalties](#rewards-and-penalties-1)
+      - [Helpers](#helpers)
+      - [Components of attestation deltas](#components-of-attestation-deltas)
+      - [`get_attestation_deltas`](#get_attestation_deltas)
+      - [`process_rewards_and_penalties`](#process_rewards_and_penalties)
     - [Registry updates](#registry-updates)
     - [Slashings](#slashings)
     - [Final updates](#final-updates)
@@ -1403,7 +1407,7 @@ def get_head_deltas(state: BeaconState) -> Tuple[Sequence[Gwei], Sequence[Gwei]]
     """
     Return attester micro-rewards/penalties for head-vote for each validator.
     """
-    matching_head_attestations = get_matching_source_attestations(state, get_previous_epoch(state))
+    matching_head_attestations = get_matching_head_attestations(state, get_previous_epoch(state))
     return compute_attestation_component_deltas(state, matching_head_attestations)
 ```
 
diff --git a/tests/core/pyspec/eth2spec/test/helpers/rewards.py b/tests/core/pyspec/eth2spec/test/helpers/rewards.py
new file mode 100644
index 000000000..41497fe60
--- /dev/null
+++ b/tests/core/pyspec/eth2spec/test/helpers/rewards.py
@@ -0,0 +1,117 @@
+from eth2spec.test.helpers.attestations import prepare_state_with_full_attestations
+
+
+def run_attestation_component_deltas(spec, state, component_delta_fn, matching_att_fn):
+    """
+    Run ``component_delta_fn``, yielding:
+      - pre-state ('pre')
+      - rewards ('rewards')
+      - penalties ('penalties')
+    """
+    yield 'pre', state
+
+    rewards, penalties = component_delta_fn(state)
+
+    yield 'rewards', rewards
+    yield 'penalties', penalties
+
+    matching_attestations = matching_att_fn(state, spec.get_previous_epoch(state))
+    matching_indices = spec.get_unslashed_attesting_indices(state, matching_attestations)
+    for index in spec.get_eligible_validator_indices(state):
+        validator = state.validators[index]
+        enough_for_reward = (
+            validator.effective_balance * spec.BASE_REWARD_FACTOR
+            > spec.integer_squareroot(spec.get_total_active_balance(state)) // spec.BASE_REWARDS_PER_EPOCH
+        )
+
+        if index in matching_indices and not validator.slashed:
+            if enough_for_reward:
+                assert rewards[index] > 0
+            else:
+                assert rewards[index] == 0
+            assert penalties[index] == 0
+        else:
+            assert rewards[index] == 0
+            if enough_for_reward:
+                assert penalties[index] > 0
+            else:
+                assert penalties[index] == 0
+
+
+def test_empty(spec, state, runner):
+    # Do not add any attestations to state
+
+    yield from runner(spec, state)
+
+
+def test_full_all_correct(spec, state, runner):
+    prepare_state_with_full_attestations(spec, state)
+
+    yield from runner(spec, state)
+
+
+def test_half_full(spec, state, runner):
+    prepare_state_with_full_attestations(spec, state)
+
+    # Remove half of attestations
+    state.previous_epoch_attestations = state.previous_epoch_attestations[:len(state.previous_epoch_attestations) // 2]
+
+    yield from runner(spec, state)
+
+
+def test_one_attestation_one_correct(spec, state, runner):
+    prepare_state_with_full_attestations(spec, state)
+
+    # Remove half of attestations
+    state.previous_epoch_attestations = state.previous_epoch_attestations[:1]
+
+    yield from runner(spec, state)
+
+
+def test_with_slashed_validators(spec, state, runner):
+    prepare_state_with_full_attestations(spec, state)
+
+    # Slash half of validators
+    for validator in state.validators[:len(state.validators) // 2]:
+        validator.slashed = True
+
+    yield from runner(spec, state)
+
+
+def test_some_zero_effective_balances_that_attested(spec, state, runner):
+    prepare_state_with_full_attestations(spec, state)
+
+    # Set some balances to zero
+    state.validators[0].effective_balance = 0
+    state.validators[1].effective_balance = 0
+
+    yield from runner(spec, state)
+
+
+def test_some_zero_effective_balances_that_did_not_attest(spec, state, runner):
+    prepare_state_with_full_attestations(spec, state)
+
+    # Set some balances to zero
+    attestation = state.previous_epoch_attestations[0]
+    # Remove attestation
+    state.previous_epoch_attestations = state.previous_epoch_attestations[1:]
+    # Set removed indices effective balance to zero
+    indices = spec.get_unslashed_attesting_indices(state, [attestation])
+    for index in indices:
+        state.validators[index].effective_balance = 0
+
+    yield from runner(spec, state)
+
+
+def test_full_fraction_incorrect(spec, state, correct_target, correct_head, fraction_incorrect, runner):
+    prepare_state_with_full_attestations(spec, state)
+
+    # Make fraction_incorrect of pending attestations have bad target/head as specified
+    num_incorrect = int(fraction_incorrect * len(state.previous_epoch_attestations))
+    for pending_attestation in state.previous_epoch_attestations[:num_incorrect]:
+        if not correct_target:
+            pending_attestation.data.target.root = b'\x55' * 32
+        if not correct_head:
+            pending_attestation.data.beacon_block_root = b'\x66' * 32
+
+    yield from runner(spec, state)
diff --git a/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_head_deltas.py b/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_head_deltas.py
new file mode 100644
index 000000000..24e3aaac5
--- /dev/null
+++ b/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_head_deltas.py
@@ -0,0 +1,109 @@
+from eth2spec.test.context import with_all_phases, spec_state_test
+from eth2spec.test.helpers.rewards import run_attestation_component_deltas
+import eth2spec.test.helpers.rewards as rewards_helpers
+
+
+def run_get_head_deltas(spec, state):
+    """
+    Run ``get_head_deltas``, yielding:
+      - pre-state ('pre')
+      - rewards ('rewards')
+      - penalties ('penalties')
+    """
+
+    yield from run_attestation_component_deltas(
+        spec,
+        state,
+        spec.get_head_deltas,
+        spec.get_matching_head_attestations,
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_empty(spec, state):
+    yield from rewards_helpers.test_empty(spec, state, run_get_head_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_full_all_correct(spec, state):
+    yield from rewards_helpers.test_full_all_correct(spec, state, run_get_head_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_half_full(spec, state):
+    yield from rewards_helpers.test_half_full(spec, state, run_get_head_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_one_attestation_one_correct(spec, state):
+    yield from rewards_helpers.test_one_attestation_one_correct(spec, state, run_get_head_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_with_slashed_validators(spec, state):
+    yield from rewards_helpers.test_with_slashed_validators(spec, state, run_get_head_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_some_zero_effective_balances_that_attested(spec, state):
+    yield from rewards_helpers.test_some_zero_effective_balances_that_attested(spec, state, run_get_head_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_some_zero_effective_balances_that_did_not_attest(spec, state):
+    yield from rewards_helpers.test_some_zero_effective_balances_that_did_not_attest(spec, state, run_get_head_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_full_half_correct_target_incorrect_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=True,
+        correct_head=False,
+        fraction_incorrect=0.5,
+        runner=run_get_head_deltas
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_full_correct_target_incorrect_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=True,
+        correct_head=False,
+        fraction_incorrect=1.0,
+        runner=run_get_head_deltas
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_full_half_incorrect_target_incorrect_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=False,
+        correct_head=False,
+        fraction_incorrect=0.5,
+        runner=run_get_head_deltas
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_full_half_incorrect_target_correct_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=False,
+        correct_head=True,
+        fraction_incorrect=0.5,
+        runner=run_get_head_deltas
+    )
diff --git a/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_source_deltas.py b/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_source_deltas.py
new file mode 100644
index 000000000..da47bd204
--- /dev/null
+++ b/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_source_deltas.py
@@ -0,0 +1,116 @@
+from eth2spec.test.context import with_all_phases, spec_state_test
+from eth2spec.test.helpers.rewards import run_attestation_component_deltas
+import eth2spec.test.helpers.rewards as rewards_helpers
+
+
+def run_get_source_deltas(spec, state):
+    """
+    Run ``get_source_deltas``, yielding:
+      - pre-state ('pre')
+      - rewards ('rewards')
+      - penalties ('penalties')
+    """
+
+    yield from run_attestation_component_deltas(
+        spec,
+        state,
+        spec.get_source_deltas,
+        spec.get_matching_source_attestations,
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_empty(spec, state):
+    yield from rewards_helpers.test_empty(spec, state, run_get_source_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_full_all_correct(spec, state):
+    yield from rewards_helpers.test_full_all_correct(spec, state, run_get_source_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_half_full(spec, state):
+    yield from rewards_helpers.test_half_full(spec, state, run_get_source_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_one_attestation_one_correct(spec, state):
+    yield from rewards_helpers.test_one_attestation_one_correct(spec, state, run_get_source_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_with_slashed_validators(spec, state):
+    yield from rewards_helpers.test_with_slashed_validators(spec, state, run_get_source_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_some_zero_effective_balances_that_attested(spec, state):
+    yield from rewards_helpers.test_some_zero_effective_balances_that_attested(spec, state, run_get_source_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_some_zero_effective_balances_that_did_not_attest(spec, state):
+    yield from rewards_helpers.test_some_zero_effective_balances_that_did_not_attest(spec, state, run_get_source_deltas)
+
+
+#
+# NOTE: No source incorrect tests
+# All PendingAttestations in state have source validated
+# We choose to keep this invariant in these tests to not force clients to test with degenerate states
+#
+
+
+@with_all_phases
+@spec_state_test
+def test_full_half_correct_target_incorrect_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=True,
+        correct_head=False,
+        fraction_incorrect=0.5,
+        runner=run_get_source_deltas
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_full_correct_target_incorrect_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=True,
+        correct_head=False,
+        fraction_incorrect=1.0,
+        runner=run_get_source_deltas
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_full_half_incorrect_target_incorrect_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=False,
+        correct_head=False,
+        fraction_incorrect=0.5,
+        runner=run_get_source_deltas
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_full_half_incorrect_target_correct_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=False,
+        correct_head=True,
+        fraction_incorrect=0.5,
+        runner=run_get_source_deltas
+    )
diff --git a/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_target_deltas.py b/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_target_deltas.py
index c30865cf0..406471c67 100644
--- a/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_target_deltas.py
+++ b/tests/core/pyspec/eth2spec/test/phase_0/epoch_processing/rewards/test_get_target_deltas.py
@@ -1,92 +1,109 @@
 from eth2spec.test.context import with_all_phases, spec_state_test
-from eth2spec.test.helpers.attestations import prepare_state_with_full_attestations
+from eth2spec.test.helpers.rewards import run_attestation_component_deltas
+import eth2spec.test.helpers.rewards as rewards_helpers
 
 
 def run_get_target_deltas(spec, state):
     """
-    Run ``process_block_header``, yielding:
+    Run ``get_target_deltas``, yielding:
       - pre-state ('pre')
       - rewards ('rewards')
       - penalties ('penalties')
     """
-    yield 'pre', state
 
-    rewards, penalties = spec.get_target_deltas(state)
-
-    yield 'rewards', rewards
-    yield 'penalties', penalties
-
-    matching_target_attestations = spec.get_matching_target_attestations(state, spec.get_previous_epoch(state))
-    matching_target_indices = spec.get_unslashed_attesting_indices(state, matching_target_attestations)
-    for index in spec.get_eligible_validator_indices(state):
-        if index in matching_target_indices and not state.validators[index].slashed:
-            assert rewards[index] > 0
-            assert penalties[index] == 0
-        else:
-            assert rewards[index] == 0
-            assert penalties[index] > 0
+    yield from run_attestation_component_deltas(
+        spec,
+        state,
+        spec.get_target_deltas,
+        spec.get_matching_target_attestations,
+    )
 
 
 @with_all_phases
 @spec_state_test
 def test_empty(spec, state):
-    # Do not add any attestations to state
-
-    yield from run_get_target_deltas(spec, state)
+    yield from rewards_helpers.test_empty(spec, state, run_get_target_deltas)
 
 
 @with_all_phases
 @spec_state_test
 def test_full_all_correct(spec, state):
-    prepare_state_with_full_attestations(spec, state)
-
-    yield from run_get_target_deltas(spec, state)
-
-
-@with_all_phases
-@spec_state_test
-def test_full_half_correct(spec, state):
-    prepare_state_with_full_attestations(spec, state)
-
-    # Make half of pending attestations have bad target
-    for pending_attestation in state.previous_epoch_attestations[:len(state.previous_epoch_attestations) // 2]:
-        pending_attestation.data.target.root = b'\x66'*32
-
-    yield from run_get_target_deltas(spec, state)
+    yield from rewards_helpers.test_full_all_correct(spec, state, run_get_target_deltas)
 
 
 @with_all_phases
 @spec_state_test
 def test_half_full(spec, state):
-    prepare_state_with_full_attestations(spec, state)
-
-    # Remove half of attestations
-    state.previous_epoch_attestations = state.previous_epoch_attestations[:len(state.previous_epoch_attestations) // 2]
-
-    yield from run_get_target_deltas(spec, state)
+    yield from rewards_helpers.test_half_full(spec, state, run_get_target_deltas)
 
 
 @with_all_phases
 @spec_state_test
-def test_one_correct(spec, state):
-    prepare_state_with_full_attestations(spec, state)
-
-    # Remove half of attestations
-    state.previous_epoch_attestations = state.previous_epoch_attestations[:1]
-
-    yield from run_get_target_deltas(spec, state)
+def test_one_attestation_one_correct(spec, state):
+    yield from rewards_helpers.test_one_attestation_one_correct(spec, state, run_get_target_deltas)
 
 
 @with_all_phases
 @spec_state_test
 def test_with_slashed_validators(spec, state):
-    prepare_state_with_full_attestations(spec, state)
+    yield from rewards_helpers.test_with_slashed_validators(spec, state, run_get_target_deltas)
 
-    # Slash half of validators
-    for validator in state.validators:
-        validator.slashed = True
 
-    yield from run_get_target_deltas(spec, state)
+@with_all_phases
+@spec_state_test
+def test_some_zero_effective_balances_that_attested(spec, state):
+    yield from rewards_helpers.test_some_zero_effective_balances_that_attested(spec, state, run_get_target_deltas)
 
-def test_some_zero_balances(spec, state):
 
+@with_all_phases
+@spec_state_test
+def test_some_zero_effective_balances_that_did_not_attest(spec, state):
+    yield from rewards_helpers.test_some_zero_effective_balances_that_did_not_attest(spec, state, run_get_target_deltas)
+
+
+@with_all_phases
+@spec_state_test
+def test_full_half_correct_target_incorrect_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=True,
+        correct_head=False,
+        fraction_incorrect=0.5,
+        runner=run_get_target_deltas
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_full_correct_target_incorrect_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=True,
+        correct_head=False,
+        fraction_incorrect=1.0,
+        runner=run_get_target_deltas
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_full_half_incorrect_target_incorrect_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=False,
+        correct_head=False,
+        fraction_incorrect=0.5,
+        runner=run_get_target_deltas
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_full_half_incorrect_target_correct_head(spec, state):
+    yield from rewards_helpers.test_full_fraction_incorrect(
+        spec, state,
+        correct_target=False,
+        correct_head=True,
+        fraction_incorrect=0.5,
+        runner=run_get_target_deltas
+    )