diff --git a/process_report/tests/unit/invoices/test_bu_internal_invoice.py b/process_report/tests/unit/invoices/test_bu_internal_invoice.py
new file mode 100644
index 00000000..9965bfaa
--- /dev/null
+++ b/process_report/tests/unit/invoices/test_bu_internal_invoice.py
@@ -0,0 +1,71 @@
+from unittest import TestCase
+import pandas
+
+from process_report.tests import util as test_utils
+
+
+class TestBuInternalInvoice(TestCase):
+    def _get_test_invoice(
+        self,
+        institutions,
+        projects,
+        costs,
+        is_billable=None,
+        missing_pi=None,
+        credits=None,
+        subsidies=None,
+        pi_balances=None,
+    ):
+        if is_billable is None:
+            is_billable = [True for _ in range(len(institutions))]
+
+        if missing_pi is None:
+            missing_pi = [False for _ in range(len(institutions))]
+
+        if credits is None:
+            credits = [0 for _ in range(len(institutions))]
+        if subsidies is None:
+            subsidies = [0 for _ in range(len(institutions))]
+        if pi_balances is None:
+            pi_balances = costs[:]
+
+        return pandas.DataFrame(
+            {
+                "Institution": institutions,
+                "Is Billable": is_billable,
+                "Missing PI": missing_pi,
+                "Project": projects,
+                "Cost": costs,
+                "Credit": credits,
+                "Subsidy": subsidies,
+                "PI Balance": pi_balances,
+            }
+        )
+
+    def test_prepare_export(self):
+        test_invoice = self._get_test_invoice(
+            institutions=[
+                "Boston University",
+                "MIT",
+                "Boston University",
+                "Boston University",
+            ],
+            projects=["ProjectA", "ProjectB", "ProjectC", "ProjectD"],
+            costs=[100, 200, 300, 400],
+            is_billable=[True, True, False, True],
+            missing_pi=[False, False, False, True],
+        )
+        inv = test_utils.new_bu_internal_invoice(data=test_invoice)
+        inv._prepare_export()
+
+    def test_sum_project_allocations(self):
+        test_invoice = self._get_test_invoice(
+            institutions=["Boston University", "Boston University"],
+            projects=["ProjectA", "ProjectA"],
+            costs=[100, 200],
+            credits=[10, 20],
+            subsidies=[5, 5],
+            pi_balances=[90, 180],
+        )
+        inv = test_utils.new_bu_internal_invoice(data=test_invoice)
+        inv._sum_project_allocations(test_invoice)
diff --git a/process_report/tests/util.py b/process_report/tests/util.py
index 85065ed0..5a27eacb 100644
--- a/process_report/tests/util.py
+++ b/process_report/tests/util.py
@@ -5,6 +5,7 @@
     pi_specific_invoice,
     prepay_credits_snapshot,
     NERC_total_invoice,
+    bu_internal_invoice,
 )
 
 from process_report.processors import (
@@ -205,3 +206,17 @@ def new_validate_cluster_name_processor(
     return validate_cluster_name_processor.ValidateClusterNameProcessor(
         invoice_month, data, name
     )
+
+
+def new_bu_internal_invoice(
+    name="",
+    invoice_month="0000-00",
+    data=None,
+):
+    if data is None:
+        data = pandas.DataFrame()
+    return bu_internal_invoice.BUInternalInvoice(
+        invoice_month,
+        data,
+        name,
+    )