Fix operator precedence involving or and addition

The addition expression was not evaluated when first operand is truthy.
ie:
(1 or 0) + 1 == 2
1 or 0 + 1 == 1

src/con_duct/__main__.py

@@ -267,10 +267,10 @@ class Sample:
     timestamp: str = ""  # TS of last sample collected
 
     def add_pid(self, pid: int, stats: ProcessStats) -> None:
-        self.total_rss = self.total_rss or 0 + stats.rss
-        self.total_vsz = self.total_vsz or 0 + stats.vsz
-        self.total_pmem = self.total_pmem or 0.0 + stats.pmem
-        self.total_pcpu = self.total_pcpu or 0.0 + stats.pcpu
+        self.total_rss = (self.total_rss or 0) + stats.rss
+        self.total_vsz = (self.total_vsz or 0) + stats.vsz
+        self.total_pmem = (self.total_pmem or 0.0) + stats.pmem
+        self.total_pcpu = (self.total_pcpu or 0.0) + stats.pcpu
         self.stats[pid] = stats
         self.timestamp = max(self.timestamp, stats.timestamp)
 

test/test_report.py

@@ -31,6 +31,16 @@
     cmd="cmd 1",
 )
 
+stat2 = ProcessStats(
+    pcpu=1.1,
+    pmem=1.1,
+    rss=11,
+    vsz=11,
+    timestamp="2024-06-11T10:13:23-04:00",
+    etime="00:02",
+    cmd="cmd 1",
+)
+
 
 def test_sample_max_initial_values_one_pid() -> None:
     maxes = Sample()
@@ -113,6 +123,16 @@ def test_averages_three_samples() -> None:
     assert averages.pcpu == (stat0.pcpu + (2 * stat1.pcpu)) / 3
 
 
+def test_sample_totals() -> None:
+    sample = Sample()
+    sample.add_pid(1, stat2)
+    sample.add_pid(2, stat2)
+    assert sample.total_rss == stat2.rss * 2
+    assert sample.total_vsz == stat2.vsz * 2
+    assert sample.total_pmem == stat2.pmem * 2
+    assert sample.total_pcpu == stat2.pcpu * 2
+
+
 @pytest.mark.parametrize(
     "pcpu, pmem, rss, vsz, etime, cmd",
     [