From 2f6c005a4eed278bbfd1fb3a0d312e440b9ea554 Mon Sep 17 00:00:00 2001
From: rstrange-scottlogic <rstrange@scottlogic.com>
Date: Thu, 22 Aug 2024 09:11:37 +0100
Subject: [PATCH] Minor update to how the pollutant summary determines if no
 AQI difference has yet been set

---
 .../summary-comparison-service.spec.ts        | 40 +++++++++++++++++++
 .../services/summary-comparison-service.ts    |  2 +-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/air-quality-ui/src/services/summary-comparison-service.spec.ts b/air-quality-ui/src/services/summary-comparison-service.spec.ts
index 38d0856e..7043fbca 100644
--- a/air-quality-ui/src/services/summary-comparison-service.spec.ts
+++ b/air-quality-ui/src/services/summary-comparison-service.spec.ts
@@ -225,6 +225,46 @@ describe('Summary Comparison Service createComparisonData', () => {
       value: 6,
     })
   })
+  it('should produce comparisons defaulting to earliest when forecast is exact', () => {
+    const forecastData = {
+      London: [
+        mockForecastResponseDto({
+          valid_time: '2024-06-01T00:00:00Z',
+          overall_aqi_level: 4,
+          no2: { aqi_level: 4, value: 4 },
+        }),
+        mockForecastResponseDto({
+          valid_time: '2024-06-01T03:00:00Z',
+          overall_aqi_level: 4,
+          no2: { aqi_level: 4, value: 4 },
+        }),
+      ],
+    }
+    const measurements = {
+      London: [
+        mockMeasurementSummaryResponseDto({
+          measurement_base_time: '2024-06-01T00:00:00Z',
+          no2: { mean: { aqi_level: 4, value: 4 } },
+        }),
+        mockMeasurementSummaryResponseDto({
+          measurement_base_time: '2024-06-01T03:00:00Z',
+          no2: { mean: { aqi_level: 4, value: 4 } },
+        }),
+      ],
+    }
+    const comparisons = createComparisonData(forecastData, measurements)
+    expect(comparisons.length).toEqual(1)
+
+    expect(comparisons[0]['no2'].forecastData).toEqual({
+      validTime: '2024-06-01T00:00:00Z',
+      aqiLevel: 4,
+      value: 4,
+    })
+    expect(comparisons[0]['no2'].measurementData).toEqual({
+      aqiLevel: 4,
+      value: 4,
+    })
+  })
 })
 
 describe('Summary Comparison Service createSummaryRow', () => {
diff --git a/air-quality-ui/src/services/summary-comparison-service.ts b/air-quality-ui/src/services/summary-comparison-service.ts
index 7bd90c01..35c42956 100644
--- a/air-quality-ui/src/services/summary-comparison-service.ts
+++ b/air-quality-ui/src/services/summary-comparison-service.ts
@@ -68,7 +68,7 @@ const reduceComparisonData = (
   const reducedComparisonData = { ...currentComparison }
 
   if (
-    !reducedComparisonData.aqiDifference ||
+    reducedComparisonData.aqiDifference == undefined ||
     reducedComparisonData.aqiDifference < aqiDifference ||
     (reducedComparisonData.aqiDifference == aqiDifference &&
       reducedComparisonData.forecastData.aqiLevel <