diff --git a/Content.IntegrationTests/Tests/Atmos/GasMixtureTest.cs b/Content.IntegrationTests/Tests/Atmos/GasMixtureTest.cs
new file mode 100644
index 0000000000..a34ccd0ccc
--- /dev/null
+++ b/Content.IntegrationTests/Tests/Atmos/GasMixtureTest.cs
@@ -0,0 +1,84 @@
+using System.Threading.Tasks;
+using Content.Server.Atmos;
+using Content.Shared.Atmos;
+using NUnit.Framework;
+
+namespace Content.IntegrationTests.Tests.Atmos
+{
+    [TestFixture]
+    [TestOf(typeof(GasMixture))]
+    public class GasMixtureTest : ContentIntegrationTest
+    {
+        [Test]
+        public async Task TestMerge()
+        {
+            var server = StartServerDummyTicker();
+
+            server.Assert(() =>
+            {
+                var a = new GasMixture(10f);
+                var b = new GasMixture(10f);
+
+                a.AdjustMoles(Gas.Oxygen, 50);
+                b.AdjustMoles(Gas.Nitrogen, 50);
+
+                // a now has 50 moles of oxygen
+                Assert.That(a.TotalMoles, Is.EqualTo(50));
+                Assert.That(a.GetMoles(Gas.Oxygen), Is.EqualTo(50));
+
+                // b now has 50 moles of nitrogen
+                Assert.That(b.TotalMoles, Is.EqualTo(50));
+                Assert.That(b.GetMoles(Gas.Nitrogen), Is.EqualTo(50));
+
+                b.Merge(a);
+
+                // b now has its contents and the contents of a
+                Assert.That(b.TotalMoles, Is.EqualTo(100));
+                Assert.That(b.GetMoles(Gas.Oxygen), Is.EqualTo(50));
+                Assert.That(b.GetMoles(Gas.Nitrogen), Is.EqualTo(50));
+
+                // a should be the same, however.
+                Assert.That(a.TotalMoles, Is.EqualTo(50));
+                Assert.That(a.GetMoles(Gas.Oxygen), Is.EqualTo(50));
+            });
+
+            await server.WaitIdleAsync();
+        }
+
+        [Test]
+        [TestCase(0.5f)]
+        [TestCase(0.25f)]
+        [TestCase(0.75f)]
+        [TestCase(1f)]
+        [TestCase(0f)]
+        public async Task RemoveRatio(float ratio)
+        {
+            var server = StartServerDummyTicker();
+
+            server.Assert(() =>
+            {
+                var a = new GasMixture(10f);
+
+                a.AdjustMoles(Gas.Oxygen, 100);
+                a.AdjustMoles(Gas.Nitrogen, 100);
+
+                var origTotal = a.TotalMoles;
+
+                // we remove moles from the mixture with a ratio.
+                var b = a.RemoveRatio(ratio);
+
+                // check that the amount of moles in the original and the new mixture are correct.
+                Assert.That(b.TotalMoles, Is.EqualTo(origTotal * ratio));
+                Assert.That(a.TotalMoles, Is.EqualTo(origTotal - b.TotalMoles));
+
+                Assert.That(b.GetMoles(Gas.Oxygen), Is.EqualTo(100 * ratio));
+                Assert.That(b.GetMoles(Gas.Nitrogen), Is.EqualTo(100 * ratio));
+
+                Assert.That(a.GetMoles(Gas.Oxygen), Is.EqualTo(100 - b.GetMoles(Gas.Oxygen)));
+                Assert.That(a.GetMoles(Gas.Nitrogen), Is.EqualTo(100 - b.GetMoles(Gas.Nitrogen)));
+            });
+
+            await server.WaitIdleAsync();
+        }
+    }
+}