fix: production with free P.I.

internal/controller/planet_test.go

@@ -173,6 +173,33 @@ func TestProduceShips(t *testing.T) {
 	assert.Equal(t, uint(106), c.ShipGroup(0).Number)
 	progress = *c.MustPlanet(R0_Planet_0_num).Production.Progress
 	assert.InDelta(t, 0.0099, progress.F(), 0.00001) // 1.(0099) drones with no CAP on planet
+
+	//
+	// groups is upgrade state
+	//
+
+	assert.NoError(t, g.PlanetProduction(Race_0.Name, int(R0_Planet_0_num), "MAT", ""))
+	assert.NoError(t, g.PlanetProduction(Race_0.Name, int(R0_Planet_2_num), "CAP", ""))
+	assert.NoError(t, c.CreateShips(Race_0_idx, "Drone", R0_Planet_2_num, 5))
+	c.MustPlanet(R0_Planet_2_num).Resources = 5
+	c.MustPlanet(R0_Planet_2_num).Population = 100
+	c.MustPlanet(R0_Planet_2_num).Industry = 100
+	c.RaceTechLevel(Race_0_idx, game.TechDrive, 1.5)
+	assert.NoError(t, g.UpgradeGroup(Race_0.Name, 2, "Drive", 0, 0))
+	assert.NoError(t, g.UpgradeGroup(Race_0.Name, 1, "Drive", 0, 0))
+	assert.Equal(t, game.StateUpgrade, c.ShipGroup(0).State())
+	assert.Equal(t, game.StateUpgrade, c.ShipGroup(1).State())
+
+	c.MustPlanet(R0_Planet_2_num).Free() // wipe planet as battle result
+	c.TurnPlanetProductions()
+
+	assert.Equal(t, game.StateInOrbit, c.ShipGroup(1).State())
+	assert.Equal(t, 1.1, c.ShipGroup(1).TechLevel(game.TechDrive).F())
+
+	assert.Equal(t, game.StateInOrbit, c.ShipGroup(0).State())
+	assert.Equal(t, 1.5, c.ShipGroup(0).TechLevel(game.TechDrive).F())
+
+	assert.Equal(t, 4346.676567656759, c.MustPlanet(R0_Planet_0_num).Material.F())
 }
 
 func TestProduceShip(t *testing.T) {