[common-go] Add test for reading psi values

Author: Furisto

Diff for: components/common-go/cgroups/cgroups_test.go

@@ -134,3 +134,56 @@ func TestReadSingleValue(t *testing.T) {
 		})
 	}
 }
+
+func TestReadPSI(t *testing.T) {
+	scenarios := []struct {
+		name     string
+		content  string
+		expected PSI
+	}{
+		{
+			name:    "psi some",
+			content: "some avg10=61.00 avg60=64.28 avg300=29.94 total=149969752",
+			expected: PSI{
+				Some: 149969752,
+				Full: 0,
+			},
+		},
+		{
+			name:    "psi full",
+			content: "full avg10=36.27 avg60=37.15 avg300=17.59 total=93027571",
+			expected: PSI{
+				Some: 0,
+				Full: 93027571,
+			},
+		},
+		{
+			name:    "psi some and full",
+			content: "some avg10=61.00 avg60=64.28 avg300=29.94 total=149969752\nfull avg10=36.27 avg60=37.15 avg300=17.59 total=93027571",
+			expected: PSI{
+				Some: 149969752,
+				Full: 93027571,
+			},
+		},
+	}
+
+	for _, s := range scenarios {
+		t.Run(s.name, func(t *testing.T) {
+			f, err := os.CreateTemp("", "cgroup_test*")
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if _, err := f.Write([]byte(s.content)); err != nil {
+				t.Fatal(err)
+			}
+
+			v, err := ReadPSIValue(f.Name())
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			assert.Equal(t, s.expected, v)
+		})
+	}
+}